Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. es, o * wu ey ‘ t ys ~ Sr te f * . i Sat ee) ie 2 o> : Sree «! a) ‘yx a, ? Loe 4 ¥ oy DIES OF PARASITES OF THE UDI Be | ee WEEVIL °° 8 my As > BS iF "i : he - ; ff oF Pe Fe .- : rs ‘ Ta # > re COTTON BOLL Bee sit ; Ue'8, Dep arn 7* “a rh ne :: +e eae 2% - H oa a be ay, i ~W. DWIGHT PIERCE, Special Field Agent. IssuprD JANUARY 21, 1908. MASS eh 3 ne "e % 7 4.7 os Che WASHINGTON: ee GOVERNMENT PRINTING OFFICE. | -: 1908. oh 3% . « > - # £22 Hog ee . bp. . my \. en) r : ed vi 4 . - ae oh : Ea * Veal ms yas aes, BUREAU OF ENTOMOLOGY. ° 9 aati ) é ; ae ORG L. O. Howarp, Entomologist and Chief of Bureau. ee ae yh << C. L. Maruatr, Entomologist and Acting Chief in absence of Chief. / a oa . R. S. Curron, Chief Clerk. og pe F. H. Currrenven, in charge of breeding experiments. aa ‘ Di _ A. D. Hopxrys, in charge of forest insect investigations. pele. ; FF. M. Wessrer, in charge of cereal and forage-plant insect investigations. = bs aX yas Bo QUAINTANCE, in charge of deciduous fruit insect investigations. oa _ . “D. M. Rocers, in charge of gipsy moth and brown-tail moth work. : 4 ea A.W. Morr, engaged in white fly investigations. oes ¥ io _ W. F. Fiske, in charge of gipsy moth laboratory. , oe. oa ~W. A. Dooce engaged in cattle tick life history investigations. sta DB A. ©. Morean, engaged in tobacco insect investigations. a 1a _R.S. Wocium, engaged in hydrocyanic acid gas investigations. 7 Ke C. J. Gruss, engaged in silk investigations. ? ; *65 oO ‘ > . . . ‘ _R. P. Currig, assistant in charge of editorial work. Maser Cotcorp, librarian. Cotton Bott WEEVIL INVESTIGATIONS. W. D. Hunter, i charge. : A F. C. Bisuopp, R. A. CusHMaNn, SPRINGER Gors, W. E. Hinps, C. E. ‘Hoop, C. R. JonKS, Wrimon Newer, W. D. Pierce, F. C. Pratt, C. E. Sansporn, C. Ss. Spooner, W. W. Yotuers, special field agents. 4 poe e ee ae . ’ . ed ' Ahn —* % % . S$. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY—BULLETIN No. 73. L. O. HOWARD, Entomologist and Chief of Bureau. STUDIES OF PARASITES OF THE CORTON BOLL WEEVIL "fa BY W. DWIGHT PIERCE, Special Field Agent. IssuED JANUARY 21, 1908. Ss S Se ss Sx s i) hills y dl WASHINGTON: GOVERNMENT PRINTING OFFICE. 1908. 2 LETTER OF TRANSMITTAL. U.S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY, Washington, D. C., July 29, 1907. Str: I have the honor to transmit herewith a manuscript entitled ‘Studies of Parasites of the Cotton Boll Weevil,” by Mr. W. Dwight Pierce, a special field agent of this Bureau engaged in cotton boll weevil investigations. Some of the preliminary results of these studies were published as Bulletin No. 63, Part II, of the Bureau of Entomology, under the title ‘‘ Notes on the Biology of Certain Weevils Related to the Cotton Boll Weevil.” The boll weevil in the United States is now known to be attacked by several species of parasitic insects. These have not been introduced with the boll weevil from the country from which the latter’spread, but they have been here for years as parasites of other species of weevils occurring in the territory now infested by the boll weevil. The present manuscript contains a record of investigations of these parasites and deals especially with the possible practical applications which may be made of the results gained. J recommend its publication as Bulletin No. 73 of this Bureau. Respectfully, L. O. Howarp, Entomologist and Chief of Bureau. Hon. JAMES WILSON, Secretary of Agriculture. 2 eg ca a bal ORL Si The boll weevil has been present in the United States for fourteen years. At this time it is doing serious damage to cotton in four States, and during the present season undoubtedly will invade a fifth. In regions like Central America, where the insect has existed for many years, there are various influences that serve to hold it in check. In this country similar influences are beginning to be in evidence. Among the direct factors in the natural control of the boll weevil that are now at work are the following: Heat and dry- ness, the native ant Solenopsis geminata, winter temperatures, proliferation, parasites, defoliation by the cotton leaf-worm, deter- minate growth, and birds. Of these, proliferation and birds have already received careful special attention, while the work of the native ant has received preliminary notice. The other factors have also been more or less discussed in the publications of the Bureau of Entomology and elsewhere, and more extensive studies of certain ones will be discussed by Dr. W. E. Hinds in Bulletin No. 74 of this Bureau. While the work of parasites, discussed in this bulletin, is not at present one of the most important factors in the control of the boll weevil, the indications are clear that its importance will grow rapidly. Moreover, the matter has special interest for the reason that it is not unlikely that practical means may be devised to increase the work of the parasites. In the United States fifteen species of insects which seek the weevil in its immature stages are known. These insects have not been introduced artificially from other countries, nor have they followed the boll weevil into this country. They have all been present for years, and have been actively parasitic upon other species of weevils found within the boll-weevil-infested territory. In fact, there are a great many closely related weevils of the genus Anthonomus, some of which are very common in parts of the cotton belt. These weevils are frequently held completely in control by parasites, and for the most part the parasites are not confined to the attack of a single species of weevil. In many cases the boll weevil may appear in a @ Not to be confused with the kelep, the introduction of which has proved unsuc- cessful. 3 4 PARASITES OF THE COTTON BOLL WEEVIL. region in which the parasites have reached the critical point of maximum parasitism, and in such cases the overflow of parasites must attack some other host, which naturally will be the predominant insect of the same group as their former host. It is therefore not at all surprising that when the boll weevil appears by millions in a new region these same parasites in the very first generation of the boll weevil become adapted to it as a new host. The distribution of the other species of weevils is limited to floral or geographical regions, and consequently, to a less extent, the para- sites are also limited. This condition is illustrated by the distribu- tion of the species of parasites which have already attacked the boll weevil. It is safe to say that as the pest advances to the East and North still other insects will adopt it as their host in the same meas- ure as it invades regions inhabited by other species of weevils. In many transitional regions there is a strong possibility that several species of weevils may be very highly parasitized and that all of them will lend parasites to the attack of the boll weevil. In such regions especially there are to be expected instances of very high percentages of parasitism. At Waco, Tex., where two regions border upon each other, a parasitism of over 40 per cent occurred at one time during the season of 1906. | There are two possible practical applications of the information obtained and recorded in this bulletin, both, however, requiring ex- pert entomological knowledge and experience. These are: (1) The propagation and collection of parasites, and their distribution in re- gions where the same species are either present in but small numbers or altogether absent, and (2) the elimination of related weevils by the destruction of their food plants in or about cotton fields, thereby forcing the parasites to transfer their attention to the boll weevil. Under the plan of artificial propagation by picking large numbers of squares in fields where the weevil is highly parasitized and placing them in cages adapted for such breeding, a large number of parasites might be obtained. The weevils should then be killed. These para- sites could be released in fields with a low percentage of parasit- ism, and the results under favorable conditions should be apparent after one generation of the boll weevil. In this bulletin will be found an account of an apparently very successful experiment of this kind, in which, at Dallas, Tex., the percentage of parasitism was brought up 9.1 per cent by the introductions of parasites from Waco, about 100 miles away. Under the plan of eliminating, more or less, the natural hosts of parasites that will attack the boll weevil (by the destruction of their food plants) no experiments have yet been performed. As an exam- ple of the possibilities, however, it may be mentioned that there is a common but easily controlled weed ( Croton spp.) grown in and about PREFACE. 5 - cotton fields throughout the South the seed pods of which are infested by a weevil (Anthonomus albopilosus) closely allied to the boll weevil. _ This weevil has three different parasites, which also attack the boll weevil. The croton weevil does not feed upon cotton or any other cultivated plants. By merely mowing down or otherwise removing the*croton plants at the proper time there could be no danger from the croton weevil, while its parasites would be forced to turn their attention to the boll weevil. It is conceivable that the encourage- ment of the croton plants or the actual planting and later removal might be undertaken in order to obtain the best possible results. Other results of practical application are recorded in this bulletin. Among them may be mentioned the fact that fallen forms exposed to the sun show higher parasitism than those shaded, due undoubt- edly to the light-loving character of the parasites. This gives another reason for the wide spacing of the plants and the use of varieties of cotton with the minimum tendency to form leafage and the greatest tendency to shed their leaves in the fall. W. D. Hunter, In Charge of Cotton Boll Weevil Investigations. * eae pra Te = Si : : CONTENTS. ol ll ae SSE “p EIS Ste Sct ee ne ne ee ee eee eee SIMI TAEERILer a LOUD. sb eee eee wee Penn OMYWOLK jsf 202s 2 eee MASS tg saa ek nos PrN UO eee mee So ee ee ol A et ne TONE (TEE NS 0) eal el ce cs Most favorable plant conditions for parasitism of the boll weevil. . Pe ERMUMG emer es ees. 2 See eee SeemetreniGa) COUSICerAtIONS.-...:.2..--. 2-2-2 eee eee cee ewe Ceiiy, EE ywlh (SST VIS Ws pee ek leak a a ee eae ea gee re PERINEMTONOLOY! 2.2.5.8 eter ed MINGMUMRE Teeth ee fe eked een oA SITS re, SITE MEDLUNOnNMUE Koro Genet tA ek gee ee. eS SDs Sree ee eee. 1. Interior work—transfer or artificial propagation of parasites... . - - Aeeldworke—release Of parasites...20-2<..1/.02 2.20.5. 2. 2240-8 Pee earariveromerainonwoOrkeressc 3.2). - 6 ok ee ieee. ee. ELE Eos bi SADIE SSG 2 ee ie a i a a eee Re Geographical and seasonal distribution of parasites......-..--.---- Eeaiseemenores ON Te Parasites. 4)... 220.222... 2222--5----++----- Ped nemaimcer On eRe, DAarasites:. <-> -2-....2-55--+-2---s2 22s ee eee eee Parasites known to attack Rhynchophora..........----.---------- Biologies of the weevils contributing parasites.........-.-.-.--.---- DLL 55 Ds Su CISC ep a Rl on UMMELUMIGunnA INO CDEONPCCUS! 52)... ste nee - eee ee ne este eee a UT age 2c Os RR eR a ILLUSTRATIONS. PLATES. Puate I. Parasites of weevils. Fig. 1.—Eurytoma tylodermatis, pupa. Fig. 2.—Catolaccus incertus, pupa. Fig. 3.—Cerambycobius cyaniceps, pupa. Fig. 4.—Microdontomerus anthonomi, pupa. Fig. 5.—Larva of Bracon. Fig. 6.—Bracon mellitor, pupa. Fig. 7.—Larva of chal- Cidoid.): 252.5 -2 be ke See ee ee eee Il. The purple mallow (Callirrhoe involucrata), a food plant of two wee- vils related to the boll weevil. Fig. A.—The buds and flowers, which are subject toattack by Anthonomus fulvus, and the capsule, subject to attack of Macrorhoptus estriatus. Fig. B.—Bud infested by Anthonomus fulvus. Fig. C.—Flower injured by adult weevil of Anthonomius fulwus << - = A= ta (ee em t= nie ts eee es ee 2 2 5 OMe 2) v2 5 2 m = 2 2 5 mils} 2 | /a| | m@/2/F|a)/2)&] a] 3218 ~~ es) ) me) aio + oS So) mt es) Oo) Pe cs] ) m |}A| A ma | P| Be wm |Ai| A | m || Be TL. as 8 1906. | JUNE eel eece ee 3, 831} 118) 3.08) (2) | (@)| (2) (2) |(@)| @ |] @ |@) @ | 3,831) 118) 3.08 yee ere ee 4,621) 210) 4.54) 247; 76) 30.76) 169; 0) 0.00 22 0.00) 5,059) 286) 5.65 MUPUSE ae os aoe 10, 342} 174; 1.68) 2,973) 348) 11.70) 2,490, 20) .80) 2,925) 192) 6.54/18, 730) 734) 3.91 September... ---- 5, 665} 286) 5.04) 1,883) 117) 6.26) 1,591) 23) 1.44) 1,140) 67) 5.87/10,279| 493) 4.79 October=— == .2-= 347} 8) 2.30) 20; 0 0.00) A eal ealercés' 860) 49) 5.69) 1, 284 58 4.51 Entire season. . 24, 806 796| 3.20) 5, ve 5a 10.56 4,307, 44 1.02) 4,947) 308 ae 1, 689 4.31 a No records made. The observations for June were made only at Victoria; those for October were made at Dallas for hanging forms and at Mineola for fallen forms. Owing to the extensiveness of the tables the figures are consider- ably condensed, but still retain the value of their records. Numerous cases of high parasitism were found, of which the following may be cited as notable examples: Number of Per cent stages. parasitized. Fallen squares: Roosevelt, Tex.,¢ September 242.2 22.5.5 a4 5 nee 69 14.4 Brownsville, Tex.,¢. September. 5. -2.) sc asede. aces a eee 1, 147 12. Hanging squares: Waco; ‘Tex... Sully 20c25. 425 ae eee ee 99 52.6 Waco; Tex.,/September 205.024:2 7. S252. ee eee 109 23.8 Cuero. Tex. August: 3 a2-Gec hoe ee oo ea eee 347 21.3 Fallen bolls: Corsicana, ‘Tex., September’ 8-222. sos... eee eee 34 5.9 Junction, ‘Tex., September,242 32s. ek oe ee ee ee ify 5.8 Hanging bolls: Marshall Tex.. ‘Aupust 222 =. 2: 95:3 Ue See eee eee 52 13.5 Trinity, Tex. , Aucust'9: 2:2)5. 2c ei ee ee es See ee 142 12.0 Waco, Tex.,; September 20: 222 3a ace ree ee 303 11.8 2 In both of these localities fallen squares would naturally be dry. ’ - BREEDING RECORDS OF 1906, 15 Numerous other high percentages were found, but these will con- vey an impression as to the promises of success obtained. In the table herewith presented only the totals for each locality are given, and in more specific tables the seasonal variation at given localities will be recorded separately. MOST FAVORABLE PLANT CONDITIONS FOR PARASITISM OF THE BOLL WEEVIL. TaBLE LV.— Most favorable plant conditions for parasitism of the boll weevil. Squares Squares Bolls Bolls Totals fallen. hanging. fallen. hanging. | otals. .|o SNS | og ‘ q Fs q Locality. Season. ml 5 pans 5 Bliss 5 a he B 3 z 5 Pe Snel ay ce geal ot tele | ae [ee ese) oo || oe [ee 9 [2/Salo |2isa! o |aisa! o |aiaa) 3 | @ Isa Sealing © lelan! © lalee! Blais & han RAE Sm |SI9B) B | Sloa] 6 IS/Oa/ S&S |Sliog! 5 S jos nM Ae ma AIA) Mm [Ae] m | Ry) om mS Be | | | | | | TEXAS. | | | | 1906. | } | | Brownsville. - . ey ee retem:| 3,095 2 Gud) s sens eealaeeals GSaiLol, Gas ihe oe seco 3, 479) 215) 6.1 yer 29. | Beeville. ...... July 12-Septem- 2, 660 36) dolar eal A294 1301.000 lec lowes 2,984] 36] 1.2 er 3. ae Christi.) July 10......-.. 438} 39] 9.0)....- eee el COW OMOS Oita eee he Lc. 458} 39) 8.5 MOURG oc 28c4-- | August 7-Sep- | 821] 70) 8.5} 209) 29/13.8) 133) 3) 2.2 | 265) 13) 4.9) 1,428) 115] 8.0 tember 3. | San Antonio...| August 15...... | S334 GMO) (O(0)) Saal ee ete Nea [eel eae ecient heute [ee 33 0) 0.0 Kerrville. ..... August 26-Sep- | Soi 4 LOso| ae 2. La eee me AQO|EN | eae Oil nk ees) Sov [ances Beale sail) Ga: tember 3. | Roosevelt... . - September 24... 69) 10/14. 4)... -- tele emee ee OMOFOK tole 143} 10] 6.9 wuncvion... .. -’.|- BdOke cee ot 129) 11) 8.2)..-.. eee LAU Ox Spl eel eet eanee| 146 12} 8.2 Mountain September Ader G3enO NOVO Seca l s-< zl oeese st Siero eel ea eee 93 0) 0.0 Home. | | (re ee September 26... Ci (0) OP(O) aS st (el See ee Bel PAA eet Seta ares |oenete 95 0) 0.0 16 miles south | September 25... ;SiIU Wen Ve. Hs Pe SOMOS OF eee seein 90 2| 2.2 of Roosevelt. | | dt (0 August 9-31 ....| 1,059] 11) 1.0} 439) 87/19.9; 80) 0; 0.0 | 189) 2) 1.0) 1,767] 100) 5.5 | Hallettsville...| August 9-30 ....| 1,040] 5) 0.4) 401) 37) 9.2; 93) 1) 1.0 | 295) 11) 3.7| 1,829) 54) 2.8 Victoria... .... June 16-Sep- | 6, 557/203) 3.0) 802) 82/10. 2) 162} 0} 0.0 | 201) 1) 0.5} 7,722) 286) 3.7 tember 1. AVION: -222).2: AUPUSTAGE =. 153) 1) 0.6} 160} 8] 5.0) 63) 1) 1.5 40| 1) 2.5 416 11} 2.6 MGO > 2 July 25-Septem-| 1, 508/128) 8.4) 460)126)27.3) 283) 5| 1.7 | 746) 83)11.1) 2,997) 342/11. 4 | er 20. | Calvert:........... August 22-Sep- | 1,054} 15| 1.4) 81) 8] 9.8} 347/ 0/ 0.0 | 181) 12) 6.6) 1,663) 35) 2.1 tember 13. | | Corsicana... . . August 23-Sep- 16} 0} 0.0) 102) 12}11.7; 34) 2} 5.9] 176) 6) 3.4) 328) 20) 6.0 tember 18. Palestine... ... ey cha 10-Sep- | 1,054) 14 A 414) 48)11.5} 209) 1) 0.4} 211) 7 3.3) 1,888) 70) 3.7. tember 4. PUM so. 21 August 9-30 ....| 1,554) 20) 1.2) 169) 21/12. 4) 949) 4) 0.4] 269) 28/10.3) 2,941 73) 2.4 Dallas a=: 22 + PueneD 17-0 c- 75 4 0.0} 150) 7| 4.6} 74 0} 0.0 |1,068) 64) 5.9 1 3e| 4 5.1 tober 6. Merrell 2202 Le September 19. Bal Oh OF Ones s= Pale AGO ORO: 22 falas ae 99 0} 0.0 Mineola....... | August 10-Oc-| 445] 9) 2.0]..... ral B7telis eS comes| ses |---| 502; 10)'250 | tober 2. | Overton....... August 23...... 197) 2) 1.0 45) 1) 2.2) 37) 0) 0.0 89} 4 45) 368 7| 1.9 Marshall...... | August 22...... 23| 0} 0.0 6} 1/16.6) 18; 0] 0.0 52 ae 5 99 8 8.0 | INDIAN ‘Slt | ie TORY. | | Fort Towson..| September 12...).....-}...|.... ert oO] X00) as peel eel ee Pres clel ael esee 521 0) 0.0 Kosoma......-. | September 14. ..|......].-.)...- 6417 Oj, O20}. 22-1: Wecribs ese sels) leeks: 64 0) 0.0 LOUISIANA. | | | Mansfield...... | August 24Sep- | 491] 3/ 0.6) 249] 7| 2.9] 211) 0) 0.0 626) 37) 5.9] 1, 577 47| 2.9 | tember 29. PADI San 2 eAMUPTIBU 23... ac 2 1,315) 6) 0.4) 633) 66110. 4) 321) 5! 1.5 539) 32) 5.9) 2,808) 109! 3.8 Orange.......- September 23-30 ASH PaD|P Lees s| sarelec ss G/ROMWOSUD aeecata ne |oee 502 5] 0.9 Minden. <-..... BENEOIUDOIS 7226). 224|- on)... - DSi ieee ROA] eal aol ecg llesre| sierallereraet 218 1} 0.5 Johnsons] August 22...... PEAY LU) TORU SE SO Bec ceed Pore el eee el Peers Pec eos 225 0 0.0 Bayou. | | LNG TRE 98 ae ee a P- 24, 806 795 3. 2/5, 123)541 10. 5)4, 307 '* aE 024 947 308 6. 239, 183|1, 689 4.3 The records from ae fhe aa end into three months, and these may be taken as indicative of the seasonal variation at a given locality. RE EE ED nn OQ OL OT J +S), ae a are 7 + as 7} oe Ka 16 PARASITES OF THE corroy “BOLL gu BEDIGMIDOL ‘B= os anno ee san ~ hoes Se ee ee ee ee 1,147 Peptember 20... 2. ssn - Shes hss sesh eee gee ao eee ee eee 265 Taste VI.—Parasitism of the boll weevil in fallen squares, Beeville, Tex. : Percentage Date. | Stages. | Parasites. parasitized. 1906. | ATIPUSE-O eo. LE ROU cee eee ie Se Re RSS Dee ees met eae 442 2 45 AIOTISG AS 2 ohh soko ccs oe Se eS em ea pe Op eee Brae | 884 2 770 NOPLeM DED 8s 22 .-: ose ao. Sac bee coos see ee ee eee ee 678 6 Af) TaBLE VII.—Parasitism of the boll weevil in fallen squares, Victoria, Tex. Date | Stages. | Parasites. | Percentage ; Bee: parasitized. — 1906. SADE G 2s 2 oso 2b ScelSs co eeie pees Cone Pee ee ee 864 15 1.8 DUITIS) 23 fers e oe ee 8 peel ae so eh aye a mene yee a See ee 667 9 1.3 RUIITLO N20) Pe sraye tei Sas leet eae Sie eas BS aro ee ee ee ee 396 11 3.0 INO AG oe Ss fe ee ee ee 9t eee Te en so ee eh 652 26 3.9 RUIN 27 es oe eS ee SEL en eer i ee 829 33 4.0 GID a Pes Se pesca ty lesa ghia em res PR nS pars ik PN 423 24 5.7 A Gee ee Pee Cone Mol See RUNG. Bir iar Co, Te 535 19 3.5 PREV ete tas Ake ence en eee Pao ne ee een a ee 560 13 ' 2.3 NEY GOO oe chee bid Soe oe Soci iS vere et eae ee 518 32 6.1 SRY eeo ele St ke ees eee Sore oh ee ee ce eee ee om 87 5 5.7 september lic .2 os sb = an3 ee ot eee see ee Se ee eee oe ete 1,026 16 1.6 TasLe VIII.—Parasitism of the boll weevil in all forms, Waco, Tex. Fallen squares. | Hanging squares. | Fallen bolls. Hanging bolls. ae: ee | ae l oe : og : og ; og : Cg Date. . 12 82) .) Sea 2 VS eee. See Dn ao Oe n 7 O-- nm ‘aD o- nm 7 co-- ® OZ r<)) oa ® Oo@2 roa) © @2 5p a 3S ao 3 a 5p Ss 3 & = a Ss |¢|53| 8/8/88! 8 )]8 |s8| 8] 4 | ss n Se |eal oa | & |eal a | A |e] mo | ow | ee 1906. | | | | | EMULE so. seu ends noe aaee 259 26 | 10.0 99 | 52) 52.6) 44 0) 0.0 22 0; 0.0 August 172... .-:..2-2.-<- 32 22" 6:2 22 3h) 1336 24 | 0} 0.0 16 0 0.0 AUIPUSE 28% 52253. oec eee 1,217] 100} 8&2] 230 451 19.5] 215 | 5] 2.3| 405 |< 477) 16 mpepltember 208222 4. eee a Gee eee eee ee 109 26 | 23.8 goo Sees 303 36 (11.8 ! ! | | TaBLe IX.—Parasitism of the boll weevil in hanging forms, Dallas, Tex. Hanging squares. | Hanging bolls. Date. Vee sas l : Per cent of : ‘Per cent of Stages. | Parasites. parasitism. Stages. | Parasites. parasitism. 1906. | | PUPUSL 202 ojo Senn coos see aes 12 1 8.5 | 26 0 0.0 September 12..............-.. 118 | 6 | 5.0 182 15 8.2 WMctober 2c -2 ee eee ee 8 0 0.0 250 10 4.0 October6.. =. 22 52 ee 12 0} 0.0 610 39 6.3 BREEDING RECORDS OF 1906. LT f The only one of these tables in which there appears any definite _ progression is the Victoria table, in which there is a regular increase _ of percentage throughout the last half of June. FIELD CONDITIONS. In order to arrive at an explanation for the obviously irregular conditions of parasitism, the figures have also been rearranged according to field conditions. It was found that generally hanging forms in wooded or cleared country were more highly parasitized than those on prairie land. The only definite comparisons which could be found were as follows: Taste X.—Percentage of parasitism of the boll weevil in forms in woodland and on prairie. Woodland. | Prairie. Locality. Date. | Hanging! Fallen | Hanging) Fallen forms. | forms. | forms. forms. 1906. oo Eo a ee ee eee Sanvem beim. os acces 2 11.2 | 8.2 6.0 6.4 °C EUED YL Sc pe ce a a September 195 2:2... .26-.- | 1 ee oe | 145 Boho Scere se | | | Stages in fallen forms on prairie land were found to have a higher general percentage of parasitism than those in woodland, although the definite case of Goliad gives a different condition. It is only nec- essary to quote the highest percentages reached in each condition to give support to these statements. The highest percentage in hanging forms on woodland was 42.6. The highest percentage in fallen forms on woodland was 8.3. The highest percentage in hanging forms on prairie was 14.6. The highest percentage in fallen forms on prairie was 10.1. Considerable contradictory matter was brought out in comparing | the parasitism in fallen forms in shade and in those exposed to the sun. The weight of evidence supports the statement that those fallen and exposed to sunlight are more highly parasitized than those which fall on moist shaded soil. Only five definite comparisons can be presented to show the irregularities which exist. Taste XI.—Parasitism of the boll weevil in fallen forms in sun and shade. W oddland. Prairie. Locality. Date. | Shade. Sun. Shade. Sun. 1906. | MIseMIBIOIO PIM. Ge ee eco oe oo oc we. LNAI 77. es Se ee a 0.54 | LeOQOr ey See. cee ee (NUL TA NS ES ee ee 2 wea 612) al ea ee A cae Aes Kapa ted (ie tos eS ye 0. 69 ies DM is ol a RIOTS Oop om siete «od ooo 2.3 1 O74 diowntotanns Le eee MNCUOMIS DEK ois ee. Sma socr. ARG G7 2.0) S 2 Se tae sce ue | REE, | | Ren an Loita ey oe 6.5 MNCLOMME ENGR 610. 82.2 at ese. 2. | TAG AA 2 eye ST IE |e eee] (eS oa 2: Coy \aeshe oo ae VCC Ai ie eS ee en BUICHSG,. 20 Sac ee cece oe 8.7 Br Sal Sas ses oe | 10292—Bul. 73—08——2 18 PARASITES OF THE COTTON BOLL WEEVIL. The highest percentages obtained in each class are as follows: Tn shade on woodland... 2-5-2220 02 30. ee oe ca In sun.on woodland: .....2-.--00 so ee ee eee $3 In shade of plants on prairie. 22... 2. -. +e eee ee 8.2 In GUN ON prairie: - 2 -22i 2.35 2 -2ies tee eee Gee ee 10.1 Should further inquiry prove that sun-dried squares are the most highly parasitized, another reason is presented for wide rows. GEOGRAPHICAL CONSIDERATIONS. By far the most important facts established by the table of per- centage of parasitism (Table IV) were elicited by using the geograph- ical map of Texas, published in the census of 1880, as a base. I. The alluvial prairie of the Rio Grande is represented by Browns- ville with an average percentage of parasitism in all forms of 6.1. II. The coast prairie is represented by Corpus Christi with 8.5 per cent, Goliad with 8.0 per cent, Cuero with 5.5 per cent, and Victoria with 3.7 per cent. Ill. The Edwards plateau is represented by Junction with 8.2 per cent, Roosevelt with 6.9 per cent, and 16 miles south of Roosevelt with 2.2 percent. This latter case was a farm with very rank growth of cotton, from which shaded squares were picked on the ground. The weevil had not been present long. IV. The black prairie is represented by Kerrville with 3.3 per cent, Taylor with 2.6 per cent, Corsicana (IVb) with 6.0 per cent, and Dallas with 5.1 per cent. ; V. The cross timbers are represented by Waco with 11.4 per cent. | VI. The eastern hardwoods are represented on the south by i Beeville with 1.2 per cent, Hallettsville with 2.8 per cent, each at the — tip of an extension of this region, and by Calvert with 2.1 per cent, — Palestine 3.7 per cent, Mineola 2.0 per cent, Overton 1.9 per cent, — Marshall 8.0 per cent, Mansfield, La., 2.9 per cent, Many, La., 3.8 per cent. Marshall is probably represented by a field on a red-land knoll, which would account for the discrepancy. z VII. The eastern pine country is represented by Trinity with 2.4 per cent, and Orange, La., with 0.9 per cent. Trinity is in a transi- tional region of pines and hardwoods, but seems to belong more typically to the hardwood region. It will be readily observed that regions I, II, 11, V, with Corsicana: in IVb, which really belongs to the brown loam region in the eastern hardwoods, and Marshall in VI, which belongs to the red-land areas of the eastern hardwoods, are the most highly parasitized, while the regions IV, VI, and VII are the lowest parasitized. The map on the opposite page (fig. 4) is presented to illustrate these statements. While it may be merely a coincidence that the places in the same belt have about the same proportion of parasitism, it is nevertheless _ Ame te *~ =.= . . BREEDING RECORDS OF 1906. 19 worthy of some attention. It is undoubtedly true that each of these floral regions is also a distinct subfaunal region, It may there- fore be expected that different weevils will exist in the different belts and different parasites operate upon these weevils. Some of these parasites may be able more readily than others to adopt the boll weevil as a host, or in certain regions there may be more species of parasites capable of doing this. In the discussion of the geographical distribution of the parasites more light will be thrown upon this question. j-—-|_. .. eS Cc. ee he ey Fic. 4.—Map of Texas, divided into geographical regions and illustrating average percentage of para- sitism of the boll weevil in all cotton forms: I, alluvial prairie; II, coast prairie; III, Edwards Plateau; IV, black prairie; IV», brown loam prairie; V, cross timbers; VI, oak, hickory, and pine; VII, pines. (Original.) BOLL WEEVIL STATUS. That there should be some definite relation between the percent- age of infestation and the percentage of parasitism was expected, on the ground that a condition favorable to the weevil should be favorable to the parasites. It was, of course, conceded that climate would be another agency to figure in the question. The year’s work is deficient in that coordinate examinations of infestations and parasitism were not taken. In another year this will be necessary in order to show whether the parasites are reducing the infestation. At present no relation can be found between pa rasitism and infesta- tion or climatology. Beeville, Goliad, and Victoria have a mean 20 ; PARASITES OF THE COTTON BOLL WEEVIL. annual temperature of 70° and a precipitation of 30 inches. At Beeville the average percentage of parasitism in fallen squares was’ 1.3 per cent, at Goliad 8.5 per cent, at Victoria 3 per cent. This condition occurs throughout the entire State. At Calvert the per- centage of infestation of squares on August 28 was 55.6 per cent and at Goliad it was 20.9 per cent, and yet the average percentage of parasitism in fallen squares at Calvert was 1.4 per cent and Goliad 8.5 per cent. A reverse condition may be cited as follows: At Cuero the percentage of infestation of squares on August 28 was 74 per cent and at Victoria it was 32.7 per cent, and the average per- centage of parasitism in hanging squares at Cuero was 19.9 per cent and at Victoria 10.2 per cent. Table XII gives in detail the trregu- larity displayed between these three factors. TaBLeE XII.—Boll weevil status and parasitism. | 2 | | First exami- |--,.. +) <. Maan Mean | sre July Mee os 008 Average parasitism, 1906. | an- , : 1%; lit nal nual A re Ls * = ] ay i ocality. _| pre- | Average per ercentage in- Ee ; ee cipi- acre. | fested. pauses a Bolls. tare ion | Wee- veri ane Hang- Plants.) yj}, | Squares. | Bolls. | Fallen. | ing. Pees ing. | Brownsville, Tex......... | 72 PAT ee eee Bees [pins ons Wena SAR | ei Fe Grogfes = = AI Bee ee Corpus Christi, Tex... ... = TAY) 30 9,412 212 71.0 | 84.0 930422. <2 0: O42 22-42 Beewillets Lex 22) 22 sas 7 30 | 8,859 300 2128) |) sat 1 LA Yel I exe ee | 0: 0:2 eee Goliad= lex: foo. ee 70 30 | 10,169 305 20.9} 1.6 S55) ses rAd 4.9 WicLOlal exes 3-3 eae 7 30 | 8,334 119 32.7 | 15.0 3.0] 10.2 0.0 ao SantAntonio, Tex... 2-2 68 25 | 12,186 101 38°00 gaz O10! | Po Ree ea Worktown, Lex: £2 5-2..-% i Valagts bial Paeieeees Sey ele 6722 1820 tp eee ea ned Fete Mat (2 = 52 |: Gnerowlex. 0 6 52. 68 | 3Q| 7,225 | 135 74.0 | 59.0 1.0 19.9 .0 0 Hallettsville, Tex......... 68 | 30] 8,056 289 1SOu| ease ar (We) 1.0 Bee Peshine Lex. oo. 2. es 68 30 | 15,580 73 19.2 S04 fol Bere | oe CME ces ae = Giddings*lex) =. 232 68 30 | 15,600 TU ine 2 SE Sa he Peak yl aoe Ss = eRe eee See ho. - WOT ROXe Hr ss ON 66 DDG ashe eee 1a Pee 2 | eo ee OO E ae eee Sixteen miles south of Roosevelt, Tex.......-- 66 eds, |b es ees | A ate yore |e esa ero QA Re ee ee ESS = Roosevelt, Tex..........- 66 7s Yul Ree [se etter eis Seay 19 es 14 Allee 0:0;|_ Sunction; Tex. .s2....: 66 Pa at ea aan Vey cawies Soe Se int eer ae Soo a eee SS le Mountain Home, Tex....| 66 D5 RSE Soe 20 | ee | eee he | ees OS ON 2a: eee ee eRe iRerrville’, Pex. 32.53 2) 66 25 Yel (es Se Sa ve Vee oS Seat es erat | eee 10355) See 2S Ne aes Drgan.bex*<.-. 2. .2-.-| 68 40 | 10,170 38 5 OSB pled lala | ee 2 Or eee eee Hempstead, Tex......--- [-= 268 40 | 12,255 84 TASER | OF ie ee eee eee ee eee ee [ccs ae Eagle Lake, Tex.....-..- | 68| 40] 5,735 89 20" 3117180" oe ee [orcas | ee Wharton, Tex..22...2..-2 | 68 40 |" 5,127 93 Ge el lee Wy Ae ed Pe Pea eR lee MaVlor, Vex <2.5. + 328.26 665]) SOL Pa ae Ee Se ae | ene 6 5.0 | 1-5 2.5 @amoeron. ex. 6.2032 | 66 | 30 | 16,317 67 73:3) 4B20% |e tse les ee ee WIS CO DOXe Roe sce 66 | 30) 138,800 49 68. 7 6. 2 8.4 PARES iif ii Csak Hillsboro, Tex........... | 66 | 30) 18,200 0 rie Eas Oe Oo te ee en |i on ae Corsicana, Tex......-..-- 66 30 | 20,524 0 38.0} 1.4 0508) IST] 5.9 3.4 Mexia, Tex..........2:--.| 66°} -30.|.48,520 0 Bil 050 ai hee ae oe oe ener phe Osilvert vlex so. 24s: | 66 40 | 11,377 196 55-6 |) 810 1.4 9.8 0.0 6.6 Palestine, Tex...........- 66 | 40 | 12,712 | 61 52.8 | 14.4 a BE 11S 4 Si AtDeNS;, POX .-2. oho eae 66 | 40] 11,568 | 21 21:6.) as cece beso | ones oe] eee MProOupe,. LOK. 2s cies Sa ceue 66} 40] 8,126 390 92) ORG 725% |e el a eee eee Jacksonville, Tex......... | 66 | 40 | 10,968 160 70:01:32: 08 koe alee ee One ee Henderson, Tex.......-.-- 1 66] 40] 7,536 | 564 | 87.65) 52.8) Sete eel See eS ee Wallas exes. < 22s sees 64 40g eee [nee oe 225 ale Os0 0.0 4.6 0.0 5.9 Merrell, Tex. s: 6.2 aces | 64] 40] 14,000 0 | 0.0 | 0.0 O,0Weee 0.01 Mineola, Tex.......-.---- 64 |} 40 1,607 10a) Set eee Pt es seek ee ET BR - Marshall Tex... = ......;: | 66 | 50 | 9,480 69 78.0 | 29.0 0.0 16.6 | 0.0 13.5 Mnnity. lex 23: =... ose | 68 50 | 9,990| 182 50.8 | 11.0 12s) 2: -4} 10.3 atkin 7 Dexs-.. 25.2 es. 68 50 | 11.320 36 GEE el (el (aa bee 4 Ie ree \ceart 2. S| eee Overton, Tex............. | 68 50 | 7,780 69 78.0 | 29.0 1.0 Ay 0.0 4.5 Fort Towson, Ind. T..... | 64 Oil“ eee 0 OOM 0:0 212 0108S seee 0.0 Kosoma, Ind. T......--.- | 64 HOW oe 0 O20 i 050 lee eae O80) |=. eae 0.0 Mansfield, La:.........-- 68 BOs [eee See | ee Br ate eee teet eee .6 2.9 0.0 0.9 MEATY VAs oo oe oe | 68 G0] eee Re ie] Rin eee en | 2 ae WS .4 10. 4 15 5.9 Orange, Da ons eccc. |.) (685) 508] so8 ee a a eee ee i st Ie ee 0:0"|-2-225 Minden: La--....-22.-.-- | 663) °= 504/E2e 0 020518 020 aul se 85 1s eae Johnsons Bayou, La....- | 70 1 Pe [Pees Ba (ee perce Ait ee 0:04 ip soe tese see 1 koe ee BREEDING RECORDS OF 1906. 21 BOLL WEEVIL CHRONOLOGY. The boll weevil has been present in the United States since 1892. Year by year it has extended its ravages, although during the sum- mer of 1896 and the winter of 1904—5 it received severe setbacks. Its territory now extends into four States, and in three of these observations as to parasitism were made. Several examinations were made immediately after the dispersion of August in newly infested fields, and at Minden, La., it was actually found that para- sitization had commenced within two weeks of the weevil’s arrival. The parasites do not follow the weevil; they are already present and native to the country invaded. Thus it is that in some parts of Texas where the weevil has been present ten or more years the parasites have not as great a hold as they have at Waco, which has only had it four years. There are probably more sources for para- sites at Waco than at other points. Tasie XIII.— Weevil chronology and parasitism. | Average parasitism. Locality. Chronology. Squares. Bolls. Fallen. Hanging. | Fallen. Hanging. Co Sri oe ee ee Weevil arrived in the August disper- |........ esr lag wee EES fee sion of 1906. First generation in | green squares collected. Fort Towson, Ind. T..... eee Le eae ei Ia. 2 Mel ele cee Seo ecto See ONO oso Se eee mosomia, Ind.-T..- io... thet CVS ROME AE Sk SES i ee lige cece: 0:03)5s0 2432] eee Le A) ee Weevil arrived in 1906, probably....-.-- OE OR ha etn a 5S | es 2 | eee Sixteen -miles south of | Weevil arrived in 1905 or 1906.......--- POT ee i | ee Oe eae eee Roosevelt, Tex. eoosevelt, Tex. 2... =.=. Weevil arrived in 1905................- 1 ei be re cee | 0f0!) 4. SS Ajcriates (aye BU Yee ee ed 8 penn ee Bi Sh BOSE he aS ae eae Sia ees eee 5.8/5 ee Mountain Home, Tex....)..... DORM SR ace ee ee nee OF OU esa sa seals: acell Lae © eee erryillie. Tex 224. ee Weevil arrived in 1904 or 1905.....-..-- OVD Eee eee 23. It a ee Writing Nex oe 88 okt Weevil arrived in 1904; set back Feb- 0.0 4.6 0.0 5.9 ruary, 1905; rearrived 1905. (ress) Fld We) a a GO oe ee Sata Son AOI Ret ae eer 12'S 18 sec IMEETOU EL Gk e227 ae | ee NG) on, Pe be SM PS ee ee ONO8| en Sake 0. Ohler eee Johnsons Bayou, La..... Weevil arrived in the August disper- OS OF S28 22 ose 2a Aol ree sion of 1904. MIATANEIG 0D 2 =e ele ne DOS e ae ee ats Se .6 2.9 0.0 5.9 PETE ESEYSED LSU Ree nh se OF Jo OSNews rk em eer 0.0 16.6 0.0 13.5 Db Parte 0 Wes ee ee Cie Bae Sete ae ak ae en oe ae eae 1.0 22 0.0 4.5 Many, Hakeee i: e. | Weevil arrived in the fall of 1903....... 4 10. 4 1.5 5.9 Corsicana, POk 2 Ne 535 Weevil present in 1903.............---- 0.0 11.7 5.9 3. 4 WACO FOKo. See eb Weevil present in 1902................. 8.4 PH fe: 17 libs SITE oO ee 2. oa oi Wieeval.presentunm 19012. 5--2.--.......- 1.2 12. 4 4 10.3 PAesune: Pex eo 8 ee | opt Roy! 2 Be ace ea ee 12 als .4 3.3 RIVER Gy BOR... -55..-- 3. ee 2 thee Ot oe Seed ee 1.4 9.8 0.04 - 6.6 ese Mex eee Loch i Hee ee Meee ee ON 6 5.0 1.5 | 2.5 Hallettsville, Tex........ Weevil present in So ee ae 4 9.2 1.0 | 3.7 San Antonio, Tex........ Weevil arrived in 1894; set back until 0; Os Socencot EP ee | eee 1897. SEG ING Eid (o> Wee se Weevil arrived in 1895; set back until 1.0 19.9 0.0 | 1.0 1896. MiICDOTIA, LOX! 22... % oN ig Os eae: a ae 3.0 10.2 0.0 5 Goliad, ee Se a Weeeval presentiin 1894.......2.-..2...- 8.5 13.8 2.2 | 4.9 Corpus Christi, Tex...... Weevil present in 1893........-.-.--.-. SLU es mata 0.0:|s-soceeeee a) > Sa Se ed 1D Say ee Se l) epedite g badteeiontes OF0} | Sooo Brownsville, Tex........ | Weevil present in 1892................. GU. hese eae 3h) | Re eeees -: | | } CONCLUSIONS. A few points of practical importance have been deduced from the foregoing general tables. - Ze _ PARASITES OF THE COTTON BOLL WEEVIL. 1. Inasmuch as the parasites are known to attack the weevil in its first generation in a newly infested locality, it may be expected that by releasing the proper parasites in a given locality the per- centage of parasitism may be increased in a very short time. Such a case was actually obtained by the release of Bracon mellitor at Peles as described in the section on propagation. . Dryness and sunlight assist attack by the chalcidoid and bra- es parasites of the weevil, as proved by the following considera- tions: (It is, of course, to be understood that this conclusion may hold only for those species and regions studied. In fact two or three of the minor species, such as the tachinids, give promise of doing most favorable work under directly opposite conditions in regions so far unstudied. ) a. Stages in hanging forms are, as a rule, parasitized to a higher degree than those in fallen forms. b. Stages in fallen forms on prairie land are generally more highly parasitized than those in wooded country, although frequently hang- ing forms in wooded country are more highly parasitized than those in prairie land. Fallen and hanging forms on unshaded ground are more highly parasitized than those on shaded soil. These facts give an added importance to certain cultural methods already advocated, viz: a. That the rows should be far apart, in order to allow the sun to dry the squares on the ground. b. That determinate varieties should be planted in order to give additional heat and light for the parasites during the cooler autumn months. That, as indicated by the present studies, dryness seems to be a most favorable condition for attack by hymenopterous parasites is quite natural, as these delicate little insects are very fond of sunlight and warmth. II. PropaGaTion Work. 1. INTERIOR WORK— TRANSFER OR ARTIFICIAL PROPAGATION OF PARASITES. It has not been a difficult matter to breed the parasites of the boll weevil. There have been used in this laboratory four distinct methods of obtaining parasites, all of which served the purpose for which they were used. In all cases where definite records of per- centage, length of stages, or nature of parasitism were required there has been a careful examination of each form (square or boll), and those forms containing parasites, or sometimes only the para- site and its host, were placed in individual pill bottles, numbered, recorded, and placed in trays for daily observation. A somewhat ee, on ae ee ee ee OR ARTIFICIAL PROPAGATION. = 2d TRANSFER less exact method has been to place a limited number of squares in a tumbler on moist or dry soil in order to make the time of develop- ment more nearly normal. These tumblers were covered with — cheese cloth and tagged. When definite records were not requisite large quantities of squares or bolls were placed in Riley breeding cages and the parasites were ~ obtained in larger quantities with less mortality, which is frequently caused by rough handling in the closer examinations. Closed boxes with numerous tubes on one side, after the pattern of the parasite breeding cages adopted by the California board of horticulture, were also used for small quantities of squares. These cages probably hasten development by increasing the heat and moisture. There was, however, another problem which proved beyond solu- tion for this season. It may be described as the effort to induce the parasites to attack the stages in forms placed in cages of various kinds. No positive results were obtained, but considerable experience was gained in the matter of breeding-cage technique. The first work was done with various kinds of glassware, closed with cheese cloth. As fast as males and females of the same species could be bred they were isolated in pairs and placed with a limited number of infested squares. These squares were fresh, flared, or fallen, in order to test all conditions. Glass tumblers covered with cheese cloth proved too dark. When dry earth was placed in the tumbler or when there was no earth, the squares rapidly dried and became very hard, and the parasites quickly died. When moistened earth was used the squares quickly molded and the parasites were killed by the fungus. When a water reservoir was sunk in the earth the parasites drowned. When glass lamp chimneys were placed on clay saucers filled with moist soil there was plenty of light and the material remained in good condition. The objection to this method is that the parasites can not be easily handled. Erlenmyer flasks gave plenty of light and were easy to handle as they have a small mouth, but they sweat profusely and the parasites were caught in the moisture on the glass. Blotters, absorbent cotton, and corks with large wire-covered openings failed to prevent the sweating. | The last attempt on this line was with mica lamp chimneys such as are used with the ordinary incandescent gas burners. ‘These were covered at both ends with cheese cloth. They are of light weight, give plenty of sunshine and sufficient circulation. For a small breeding cage they are very handy in many ways. But the parasites did not attack the weevil even in these cages. In all of the above types of cages the life of the parasite was hardly a day. In wire types of cages the parasites lived several days. In the following, several of each sex of the parasites were used. , o4 PARASITES OF THE COTTON BOLL» WEEVIL. The first type was a cubic cage made very easily by using strips of cork for the framework and fine meshed wire (known as 50 to the inch, but really 35 and 45 to the inch) for the sides. One side was — fixed with two openings which were closed on the inside by a tin shutter. The lower opening was round, and in this a cork with a glass tube through it was placed before the shutter was raised. Thus the parasites, being attracted to light, could be quickly removed by darkening the sides and allowing the light to enter only through the tube. When the shutter was raised higher it exposed a larger opening through which material could be passed. With this first cage as a type various modifications were contrived, all with wire fronts, shutters of various kinds, and corked holes for the admission of a tube or for passing in small objects. Cigar boxes became the bases for these cages. Still another modification was a wire cylinder corked at one end and with a smaller cork centered in this for the removal of material. The other end was covered with cheese cloth. It was found impossible to provide plant conditions in a small cage unless the plant were actually transplanted or grown from seed. A branch of cotton withers so quickly that experiments of this sort were of no value. Both kinds of tubes were tested on the plants, but the mica tube caused a heavy sweat and killed the branch it was on; the wire tube was too heavy. All of the plants placed under the large parasite- tight cages with glass sides died before results could be expected. 2. FIELD WORK—RELEASE OF PARASITES. The release of parasites in the field was not commenced until September 12 on account of the small amount of material gathered prior to that date. Notwithstanding that fact the results give an indication of success. On the laboratory farm at the top of the hill there were released 35 parasites on September 12 and 38 on Septem- ber 15. These parasites were of three species. An examination of hanging forms was made in this part of the field and another down the hill at the opposite side and about 350 yards distant. At this time the check area (‘‘B,” fig. 5) showed 1.9 per cent higher para- sitism than the parasite area (‘‘A,” fig. 5). Twenty days later, on October 2, like examinations were made with the result that the percentages were reversed; ‘‘A’’ showed an increase of 2.6 per cent and ‘‘B” showed a decrease of 6.5 per cent; that is, ‘A’? was 7.2 per cent more highly parasitized than ‘‘B”’ and showed a real gain in parasitism of 9.1 per cent. On October 6 this examination was followed by another, and, although the difference was less, ‘‘A’”’ was 3.9 per cent more highly parasitized than ‘“‘B.” Plat “‘A” was next to a fence and separated from another field of cotton by a road and a FIELD WORK—RELEASE OF PARASITES. 25 high hedge of Ambrosia trifida with scattered Solanum rostratum. As a further check on the experiment the nearest part of this field (‘D,” fig. 5) was examined and proved to be parasitized by 2.1 per cent less than “A.” On the contrary, the farther part of the field (“K,” fig. 5) showed 5.8 per cent higher parasitism than ‘A.’ The conclusion was that ‘‘E” and ‘“‘D” did not influence ‘‘ A.”’ The results are given in Table XIV for the entire experiment, and also according to species. It is believed by the writer that it was the release of Bracon mellitor which accomplished the change. The evidence upon which this belief is founded is both positive and negative. Bracon mellitor was not found breeding upon any other species of weevil in the vicinity, and yet the examinations showed an increase of parasitization by this species in the ‘‘ parasite COTTON 8 X ° g » x K zg SY 9 & Fig. 5.—Diagram of cotton plantation of H. O. Samuel, Dallas, Tex., of 644 acres, showing location of plats where observations and experiments on boll-weevil parasitism were made. (Original.) ‘ area’’ opposed to a decrease in the ‘‘check area.’ Catolaccus incer- tus, although released in large numbers, did not take hold at all,nor was it found breeding upon any other species of weevil in the vicinity. A few Cerambycobius cyaniceps were released, but the only trace of parasitization by this species was found in the original check. And yet this species was bred from Larus musculus in the stems of Poly- gonum pennsylvanicum near by, and also from Trichobaris texana Lec., in the stems of Solanum rostratum adjacent to ‘‘A”. No Eurytoma tylodermatis were released, although this species was abun- dant throughout the field. It is known as a parasite of Larus scro- bicollis Boh., which breeds in Ambrosia trifida stems. Immense numbers of this plant were growing along the road adjacent to ‘‘ A.” In order to show that plat ‘‘E,”’ which was highly parasitized by ~ y < ur 6“ A? dermatis in ‘‘E” evidently had no influence upon the presence of the fact may be cited that the higher percentage of Hurytoma tylo- Ail =. Le * pecies in NB did not influence the numbers of that s EC haat. = - zt: PARASITES OF TH Bracon mellitor, 26 Total. Re? Area 100 yards from ‘‘D.” “poztqzs -w1ed oBBU9010q *pozipisvaied saB¥ys Jo JoqUINN *[TA00M oud? jo sosB4S | *poztqis ~B1 vd 088700010, / 10 | 39 | § Total. 8 247 ‘poztpiseied SodBys JO Lo(UINN "TLAOOM ayy Jo sodvig cE TOM Avey: across road. area. “°C.” Check Check area. <“B ”? Parasite area. TaBLeE XIV.—Release of parasites of the boll weevil—Summary of all species. that species in ‘‘ A.” *poztqis -bred OBJ WILT from ‘‘D.” 11 |12.9 | 622 “BE.” Area! 100 yards | 5.0 | 96 ‘poziqis ered $93B}s JO JOQUINN ll De? Area | across Si *poziyis vind 038) U0010,.7 *pozipiseced. SsodB48 JO LOqUNN *TIA00M 944 Fo s03B49 ‘paztys -BIvd 998 UOd10g *pozipisvred sodv4s JO LO(UINN | “TLAOOM. 944 JO sodeyg | “poztqis -vivd o8¥ 4uU0d104 | Area 100 yards from ‘‘D.”’ *poztqIs -vivd OBBIUWILOT “poziqisvaed /So3B4S8 JO LoqUINN Area =z ‘poziqisvred = sodBys JO LOGUINN cy . *[LA0OM e94Ut JO sosuyg *pozipis -vied o384U00107 ‘pozipiseed so03B48 JO LOQUIIN *TIAOOM ©uU4 JO sodBI9 "poz tzis -Be1ed o3v 100010 gq *[LAO0M 9U4 JO sosvyg across road. ae Dp? *TIAOM. 094% JO sosuqg | *poztqis -nred o887U0010,, ~~ “pazipisvied soseys JO 1oquUInN *TIAOOM. ou} JO sosvig ‘pozuyis -eied odBqUOO10 ‘poziisvavd sosRys JO LoquWnN *[TAOOM a9yu4 JO sosrq9 “poziqIs -vivd 034000107 *pozipisvied sodB4s JO LOqUINN *[LAOOM 944 JO sosuqg Date. ~ ‘ 5.8 | 180 | 14 Released 27 °, | 120 | Sept. 12:_-..- _ ./218 | area. “B.” Check | ‘C.”? Check area. *poZzIqs ~vied esa uedIed ‘pozipiseaed: Sodey4s JO LoOQUINN “poz ips Bibd 808848 JO JoquUINN *[LAOOM 944 Jo sodnqg “PpoZtyIs -B1Bd odv 1 U00I0g area. “[IA00.M auy jo SOBBIS «¢C.?? ‘Check “poztqis -Bied 031000107 *poziyisBied 4 |2. 22 Check area. sodvys JO Loq(UINN *TIAOOM 9 q aE fifo) 803848 180 | “BR” ‘poztyiseied $038 18 JO LaQUINN *[TA00M oy + yo So3dB4g *poziqis “vied 038} U0010,J ‘poziyiseied Sso3vy4s JO 1oqGUNN *TLA0OM out JO spsRIS TaBLE XV.—Release and parasitism of Bracon meilitor. Parasite area. SiGe Released 35 9, Bh te 95 | “cA? SeODblo-- o> “poztyis ahs See luce ed ‘poztpisvared | _SodB4S JO IOQUINN *TIA0OM. Onede 0 eee i eo se Shh Date. “poeztyzIs -Bivd eau cepied: 2 | 1.66 Parasite *pozyqisvied so3v4s JO LaquUINN TaBLE XVI.—Release and parasitism of Catolaccus incertus. area. 120 | Released 14 @, COA? Sept. : *[IAOOAMA a9Ut JO sosdvqg Date. 2 ae .| Released 20 @, a Woe Sept. 15..... Ave Sao ~ Te ee ee ee ee A Se Se Se eS oe cS —— ees 7 LEASE OF PARASITES. 27 a p N 7ORK— oe ? TaBLe XVII.—Release and parasitism of Cerambycobius cyaniceps. ” “Rn.” Area ~ “D.”” Area | “109 yards | Total. “A.” Parasite *‘B.’’ Check “C.”” Check across road. from “ D.” area. area. area. | ° na >) Dn © n ® ‘ o na ' ro) ea |i = |& @ ia |@ |@ |e 18/8 |s Ble la lesl8 ls ley 42 o| 3 > ao -|s8 +2 | ~» |S|s re o\ 3 43 a0 eg] &. ;\2's| 3 ;\2's|o3 eee.) eS om, e326 wo loa! oF J ° 44 SI oD lui la | oF HS ve | OO — i es) HE [SB G8 |SElS5| SS | os [os BR [o S[oa| PS SESE HS | oe (SE &S Zixalss| Sisalss 8 |ne|Sa | Sig alss\_ sisgiss Blk alos ae \S4| a | 2 |58| 5% ne 2a) oa 9 Flo 3| 5a a Blau ea | oe Ze GG 8 gal S 80 Geld |& |8e 8S |t |g@alS |e sais |& |sais Serie pexis j2es |S BAIS ig |3 15 ls |2 |o |S 3 13 D Z ra m |e | mH ia ie io |j& | \a |& mH nm |e |e sale 120} 0} 0.0] 180| 1 | 0.55).....|.-..|-----|---- pa ee 200 1/03 | | | 1d. | nt 951 Of .0| 1623] 0| 0.0|----.-|---- Je-=-|oe3" Bless lee closet oeus at pe Oa mae 125 Bri ye cay (Cee ee 918 | 0 | 0.0 | 96| 0| 0.0 | 622) 0 0.0 Wee lar |, Coca 0 0.0 Tapue XVIII.—Parasitism of Eurytoma tylodermatis. (oo) Ae ee a ee EEE Cn “ce ”) A) Parasite | “B.” Check | “C.” Check | “D.” Area yee |S omoeel area. area. area. across road. cond . ae \ | | — ——— >) nD \ Oo n ' o n 1 <>) n \ Oo n 1 © n ‘ Fo a Q 3 Q 3 E x Bo Ia a % B a & f =| aq 80; im 14 8; = q bp aI fe) bo ; KR Date. Peocivoeei i: (ss) es |* Sela .[P j|sgie.| Sdla |? leyle a4 |22e = si" 8loa0d aN ste | ores laailga oI O'S 8 | 70 bi peg eS ley N [<>] we ay SS Ds eS le Os et mt ley ES es) Stet lay N Ors aw NO SE IeS] 8 | oe (cs) 28] 08 |e) PS lo BSS BS lo g/CEl a8 |°8 Cslas Pitales | Seaes|_ elssles S\nalSo| sipalse| eis 3les ae las| Ga | oF \ok| oe aE lSki Sa |eelog| ga |sFlek| 5a neo fh o i) ee) o i) = o o as o o — HH) © o 4 io 1) Gal to issio wo |8Aio bm |EAaio jw |Bsl1S t |esio oS 3A] & 3 g Py ES] 5 a 3 |s iF a |g3A| 3 53 AE re) 4 > s ~P 12 K re) L = 2 io) Z a mM Z py nN Z Ay nm IG Ay ™M A rah TD 7 | Cy SS fa face be ee Satie cece ai Wh SH Sept. 12 ..... 120} 0 | 0.0 | 180 3 /1.66 | 2 ale eal4ess3 bes 66ee ReSS3 SSS crc ia. 300 By ale(t) Le Om 1)-2)| 2.10) 163-0) .0 |----- | Sod hosel ake heck ISCRe Aer! Ree bee fe 258 | 2)| 0.7 J) eee 18. A .54 | 125 TE) le ate 0h) ee ee | 918| 2 | 0.91| 96 | 6 [6.25 | 622 LOW 126 OO SVG ESS a a ee Pastore 2g PIT GLOM MeN leeoletcs becsl-e o-|a ae 247| 0| 0.0 | III. Parasire Breeprnc Work. Four new primary parasites of the boll weevil have been bred this year, and several definite cases of predaceous attack have been observed. There are now known 11 primary hymenopterous para- sites, 1 primary dipterous parasite, 2 acarid parasites (at least), 2 coleopterous enemies, and 2 ant enemies which attack the weevil stages in the cotton forms. They are as follows (insects which attack the adult weevils are omitted from the consideration) : PRIMARY PARASITES. Hymenoptera. Chalcidoidea. - Torymide, Monodontomerine. 1. Microdontomerus anthonomi Cwid. (Texas). Eurytomide. 2. Eurytoma tylodermatis Ashm. (Mexico, Texas, Louisiana). 3. Bruchophagus herrerx Ashm. ( Mexico). Encyrtide, Eupelmine. 4. Cerambycobius cyaniceps Ashm. (Louisiana, Texas). Pteromalidz, Pteromalinz. 5. Catolaccus incertus Ashm. (Texas, Louisiana). 28 PARASITES OF THE COTTON BOLL WEEVIL. Hymenoptera—Continued. Ichneumonoidea. Braconide, Sigalphine. 6. Sigalphus curculionis Fitch (Texas). 7. Urosigalphus anthonomi Cwid. (Texas, probably Mexico). 8. Urosigalphus schwarzi Cwid. (Guatemala). Braconine. 9. Bracon mellitor Say (Mexico, Texas). 10. Bracon dorsator Say (Texas). 11. Undetermined braconid (Texas). Diptera. Tachinide. 12. Myiophasia xnea Wied. (Texas, Louisiana). Acarina. 13. Pediculoides ventricosus Newp. (Mexico). 14. Tyroglyphus breviceps Banks (Texas). PREDACEOUS ENEMIES. Coleoptera. Cleride. 15. Hydnocera pubescens Lec. (Texas, Louisiamia). Cucujide. 16. Cathartus cassie Reiche (Texas). Hymenoptera. Formicoidea. Myrmicidz, Myrmicine. 17. Solenopsis geminata Fab. (Guatemala, Texas, Louisiana). Formicidz, Formicine. 18. Formica fusca subpolita perpilosa (Mexico). HYPERPARASITES. Hymenoptera. : Microdontomerus anthonomi Cwid. Eurytoma tylodermatis Ashm. Accidental on Bracon mellitor Say. Cerambycobius cyaniceps Ashm. POSSIBLE PRIMARY PARASITES. Hymenoptera. Catolaccus anthonomi Ashm. (Texas). Two species of entomogenous fungi, Aspergillus sp. and Cordyceps sp., have been recorded as probably parasites of boll-weevil larvee. OCCURRENCE OF SPECIES. 1. Microdontomerus anthonomi Cwfd.* This species was collected as follows: Goliad, Tex., September 3, 1906, 1 bred from Bracon mellitor cocoon; Cuero, Tex., August 31, 1906, 1 bred from Bracon mellitor cocoon; Hallettsville, Tex., August 30, 1906, 4 females, primary para- sites upon A. grandis; Waco, Tex., August 28, 1906, 2 females, pri- mary parasites upon A. grandis; Waco, Tex., August 29, 1906, 1 male, 3 females, primary parasites upon A. grandis; Waco, Tex. August 29, 1906, 1 male, bred from Bracon mellitor cocoon. @ Crawford, 1907a, b. OCCURRENCE OF SPECIES. 29 } The range of the Microdontomerus is evidently western. 'Twenty- | three per cent were secondary parasites. — 2. Burytoma tylodermatis Ashm. This species, while not veryimpor- f tant in any part of the State, is very well distributed. It was recorded continuously after July 12, 1906. Specimens were bred from mate- ‘rial collected at Beeville, Brownsville, Calvert, Cuero, Dallas, Goliad, Hallettsville, Overton, Palestine, Trinity, Victoria, and Waco, Tex., and at Mansfield and Many, La. No records were obtained from Corpus Christi, Corsicana, Junction, Kerrville, Lula, Marshall, Mine- ola, and Taylor, Tex.; nor from Orange, La. Specimens were sent in | by Prof. A. L. Herrera from Allende, Coahuila, Mexico, with the note that it was abundant at that place. 3. Bruchophagus herrere Ashm. This parasite has not been taken in the United States. It was described from Coahuila, Mexico. 4. Cerambycobius cyaniceps Ashm. This parasite has been taken at all points investigated except those in the Edwards Plateau region. 5. Catolaccus incertus Ashm. This parasite has not been taken at Overton or Marshall in northeastern Texas, but is common at all other points investigated. 6. Sigalphus curculions Fitch has not been recorded since the first specimen was bred at Calvert, Tex. 7. Urosigalphus anthonomi Cwfd.* One female was bred from a cocoon in a weevil cell from material collected September 5 at Browns- ville, Tex. As the former record was also from Brownsville, this species _ may be taken to be Mexican in origin. 8. Urosigalphus schwarz. Cwfd.t From 300 squares Mr. E. A. Schwarz and Mr. H.S. Barber bred 5 females and 1 male of this newly described species at Cacao, Finca Trece Aguas, Alta Vera Paz, Guate- mala, during April, 1906. 9. Bracon mellitor Say was bred from all points, except Overton and Marshall in northeastern Texas. The form known as Bbracon xan- thostigma has only been bred from the weevil between September 16 and April 28 in the various years of this investigation. A specimen of this species is recorded on the Bureau of Entomology files (D. A. 6424 (412)) as bred from the boll weevil at Coahuila, Mexico, Novem- ber 15, 1902, by Professor Herrera. Specimens were sent in by Pro- fessor Herrera from Allende, Coahuila, Mexico, during 1906, with the notes that they were quite common. 10. Bracon dorsator Say was not bred until October in 1906. It is only known to occur between August 2 and December 17 in Texas. It is probably another instance of seasonal dimorphism and identical with Bracon mellitor. 11. Braconid. One female of this species was bred September 1 from a cocoon in material collected on the ground at Victoria, Tex. The specimen was lost in transit. a Crawford, 1907a, i - 30 PARASITES OF THE COTTON BOLL WEEVIL. 12. Myiophasia «nea Wied. Pupz of this species within the lar val skin of the weevil were taken from material collected at Many, La. (3 specimens), and Waco, Tex. (1 specimen); also one specimen in imperfect condition was found in a small boll collected at Victoria, Tex., July 12. Its puparium was within the skin of a weevil larva. 13. Pediculoides ventricosus Newp. is a common weevil parasite in Mexico. 14. Mites were frequently found to have destroyed the weevil stages in fallen squares, especially at Calvert, Tex. Tyroglyphus breviceps Banks was described as a weevil enemy from — Victoria, Tex. ) i ' ! \ 7 1 H H I 7 ' ! ' tee a= of = ow Gs om a ol ee et is ' ' ' oe eee ' i 1 on wm hee as ' t It meilimwe ' ( t Sl T ' i t t ' t t ' t ' ! ' | he ! ' i ' ! Sn —— \ —se~sl--= 2 4 Fig. 6.—Occurrence of predominant parasites of the boll weevil in Texas and western Louisiana e showing-—— || Oecurrence of Catolaccus incertus. = Bracon mellitor. \\ Cerambycobius cyaniceps. ||| Eury- toma tylodermatis. |/ Limits of predominance of single species. /Limits of two predominant species. (Original.) 15. Hydnocera pubescens Lec. was found frequently to have killed — weevil stages. Records of this predatory habit are from Browns- ville and Waco, Tex., and Many, La. In a great many other cases evidence of its predatory nature was less reliable. 16. Cathartus cassiz Reiche was found several times to be preda- ceous in its larval stage upon the weevil. Catolaccus anthonomi Ashm., determined by J. C. Crawford. Four specimens practically identical in character with the type of this species were bred from cotton squares collected October 12, 1906, at OCCURRENCE OF SPECIES. 81 Waco, Tex. Although a large quantity of these squares were exam- ined, no specimens of this species were obtained except from the general breeding cage. The species is known as a parasite of an ‘wstivating weevil (Anthonomus signatus Say), and it is possible that in the fall the parasites may attack Anthonomus grandis. GEOGRAPHICAL AND SEASONAL DISTRIBUTION OF PARASITES. Only four of these parasites are at present of any great importance. In arranging the percentages of each species with regard to the total number of parasites the following table (Table XIX) has brought out sufficient data for the production of a map (fig. 6) which shows the area over which any two of them are predominant. Thus, over the entire western half of the area studied Bracon mellitor and Cato- laccus incertus are the most active, while in the Northeast and Kast Cerambycobius cyaniceps shares the importance with the other three in more or less limited belts: Tapue XIX.—The seasonal distribution of the parasites. Bracon | Catolaccus Eurytoma | Ceramby- ‘ : tyloderma-| cobius cy- | ea mellitor. incertus. CE aniceps. Locality. Date. ber of) = : a S. == para- a eer ner 7 eI= sites. aia _|Num cent- Aum cent- Aun cent- o age. age “| age 1906. Beeville; Tex: ~/-<-- ----- bt byl Paes = epee 26 8 5 | 19.2 Zale 1 3.8 (oe a i ene August 8...-..---- 2 A(T" 0)4( 0) Wes Sng) | RN | eioeee) Rocral sor. WOsEAavoste-se =e August 13...-.---- Gy A Gs a LR He Sees Deere Pires ect ee Qesn nee te ea e= September 3. -..---- 6 GeOOOulesle Lbs tee Sa --|- <5. a). ele Brownsville, Tex. -.------ giyweet teak. -=- 43 38 Fea ey Ay [ee el acta ee icra oe ere 0) 55 (eee see ACS ee eee 119 39 77 | 64.7 sel) SPA Bac ae = lite oes Obs oo2 seas oe eee (aT Soe Sen RE | nie ero kc) [ea te) Uae er eral Ure Da IO) a tas ate towerne =i September 5...---- 155 50 85 | 54.8 1| 0.6 2 1.2 (Dee ee Oe edo eere September 29. .---- 53 12 AQT GA) nea sets |ae aces [pee = let Galvert, Oks. -so ots == August 29.....---- i | et Se See hee a ee ae eon etre Py eb bch N70) 2) eh errs September 12....-. 21 6 4 | 19.0 3 | 14.2 | 1 4.7 Lien. See eee October 2.--------- 0 A MORO ise Sealereeee 216-20: 0) 2ee esl eee LOSS Se See October 6...------- 39 19 1| 2.5 9) 523.0) \se2 see |e Dee ee oe eee October 10..------- 5 GS AKO OS easece| lacsoce easter Pees ere |e 2 OMMUE LOS. soe aso - = ARISE 1-5 == ---- 7/\\dae hel Renae | Lees Sel eee ee Sh ees eae ec er sees sate eam er September 3-..---- 108 73 22 | 20.3 Silent 2 1.8 Hallettsville, Tex....--- AUTISUSyO..- -\- = += --- 15 3 3 | 20.0 2) 13.3 1 6.6 ice is 2 Ps August 30....----- 39 7 4 | 10.2 7\.17:9; 8| 20.4 Junction, Tex......----- September 24 12 10 F\\ 16572 |_ 2. con |s= === ~|aae == ee Kerrville, Tex.....------- August 26....----- 6 3 D5 leSoess es | es Beers 2 Oe Saar a September 3..----- 5 2 1 220" 0410 oes beeen =e ae Mansfield, La.....-..-.-- AMSUSE 245.5 2% 4-5 - 47 5 2) 4.2 | | 2.1 36 | 76.5 RET Ge «as bo eles nie = August 23....-.-.-- 109 6] 5.¢ 12 | 11.0 8 | 7.3 45 | 41.2 Marshall, Tex.--.<--.--- Awigust22-.2..-.:- 7) | [Cee Leni eariec) Neem ogeesy emer peer |e g. 6| 75.0 Mineola, Pexs. > =-.<----- Rasdsr AOL... .---- Hh er We Se ia cele em ws | ern nla oe Se come MELO Relics <= --- = 9 4 AN AAA ord omen See =e [sc cer ne oie PERI: Tiler sn hw a « September 30...... 24 eae, Coane Fhe Rid ORE Pees) So [eee Overton, Tex. ..-..-..--- August 28. 02. ---- > 6 ee ee a Pere eee 1 | 14.2 2| 28.4 Palestine, Tex...--.------ f Anes 10... --.-.-- 70| 12 10 | 14.2 6} 8.5 7} 10.0 Roosevelt, Tex.....----- | September 24...-..- la) 1051 BN 50:0 locon od ecateet| en aee |e === |e een eee Sixteen miles south of | September 25..-..-- ud era el be cen LYSOL OS Se see eee eee ee oo Roosevelt, Tex. | | Ji) LO i> Fa VAAPAIB LO! -.5=-.- - i 2 fa 5 pam bie ad VO a 2) 18.1 |. ccae-[e asd = EME EO Rienc osc ena | August 9.....----- BOs 12. 17.3 9 | 13.0 | 7 | 10.1 12) Wes Doslct lee... ..-.2_-| August 00.......-.- 14 | Ay ere a ers ry ea eee eae 14.2 By PARASITES OF THE COTTON BOLL WEEVIL. TaBLeE XIX.—The seasonal distribution of the parasites—Continued. Eurytoma | Ceramby- tyloderma-| cobius cy- Total mellitor. | incertus. um | _ Bracon | Catolaccus | num- tis. aniceps. Locality. | Date. ber of - = - para- ; er- |y; Per Per Per- sites ree | cent-|Nam- ent- pitas cent- pices: cent- age * | age. | age. eT. | age 1906. Brictorla;; Dex. 2.2 c8 5: WMG Ap tec eee etee Ee eee eee oe ee oe oes eee ee aaa Babee fee Ob eer esse ese oes Ap bE sT=\7 5 ae pe 9 2 ESAS 2 | 22.2 Beye Meret oe i OP oe nee ee eae JUNG 25 ee eee 11 2 | 18.0 6 |-osforl Sea ase eee eee 1 DY ey eh eR ee ae JUNG ZO Ree soe 20 10 | 38.4 P| 20 9 lee eels kee [ate ae DOSE son eo eee Abia (EV 74 (pes ea Ss 33 15 | 45.4 8 | 24.2 1 3/0/22 eee DD) OAR er ae Se ee JUNG ZS ee See PALS a ae ea af eee oe ae ee oN Se ee ee 1D 10 se a I ea ce Jey gee ee ee oT [ieee [neat erie be a8 | ay Pe ees 1D Yo tis a a aves ae chore tage Jays De eee ees 13 ere pee Pee A Fe eee Era ert a IS 1 ee Ryo ee eet ae Tuilys9 ie ae eee eee 3 a 2 Ms aa eee Re IP Doct oe 6 ay ts July dh <2 eof yee 32| 18] 56.2 21 6.2 ial BA ID) Oe re eee JUL yen ee eee 5 OL POOLOMAS ase rpm eee, OP aR) ce ne DO ee i= a5 See a sahne September 1......-. 75 45 | 60.0 3 | 4.0 3] 4.0 11 14.6 WWSCOs TOE ok aes nace TubyA2b Se | 78 25 | 32.0 6 | 7.6 | 3 | 3.8 4 5.1. DOPE AE eee st Aas ANISVSUGUL > eee 5 1 | 20.0 1 | 20.0 | 1 20 OSes See a 1D 0) Ae ee See ete | AUISUSEZ8E ae 2 sees 83 AB SAL See aoe 7 8.4 25 | 29.8 Dek Agate SMa ee | August 29........- 114|} 64/561] 11| 9.6 3| 2.6] 12] 10.5 DOP ee the oo a eee September 19...... 36 19 | 52.7 2 5.5 8 | 22.2 20 | 55.5 IDO) SG sameeren or ! October 122222 522-2 SL 222 s]ec SSE ae eee ee a ee eee ee These figures show very plainly the range of each species and have therefore been used to form a map of the two predominant species throughout the State. The centers of the areas predominated by Catolaccus are Brownsville, Tex., and Orange, La. The influence of Bracon radiates from Goliad and Corsicana, Tex. The center of predominance for Cerambycobius is Marshall, Tex. Eurytoma becomes an active agency at Dallas and Overton, Tex. BIOLOGICAL NOTES ON THE PARASITES. 1. Microdontomerus anthonomi Cwfd. The Torymidz have always been considered by Dr. William H. Ashmead as parasitic on Diptera. In addition to the records of parasitism upon the boll weevil, which are given on a preceding page, one other specimen was bred September 13, 1905, at Mexia, Tex., by F. C. Pratt from Brachytarsus alternatus Say, breeding in the stems of Sideranthus rubiginosus. The species is not at all abundant, and has only been collected in cotton forms between August 28 and September 3. It is perhaps a one-genera- tion species, although it may have some other and still unknown host. There is but one individual to each host, and the host may be in the larval or pupal state when attacked. The sexes occurred in the proportion of 2 males and 11 females. In order to ascertain the length of the developmental periods, the following scheme had to be used: The maximum period from col- lection to maturity is the nearest approach possible to the total developmental period, and next to this is the total period in a Bracon cocoon in case of hyperparasitism. The maximum period from the observation of the larva to maturity is the nearest approach possible “ ar) > ; ' 3 ‘ = _ BIOLOGICAL NOTES ON THE PARASITES. 33 to the total period passed as larva and pupa. The exact length of the pupal period may be defined as between the maximum period from observation of the pupa to maturity and the minimum period _ from observation of the larva to maturity. Thus it will appear -{ from the following that the total developmental period is over _ twenty-three days, and the pupal stage lasts from six to nine days — during August and September. i> = Taste XX.—Length of developmental periods in Microdontomerus anthonomi. ie — | Collec- : | Pupa Tan | Sion ny carta ‘toma con | Development. Locality. Date. eee | jrt’Y to ma- iturity.| | | | Maxi- | Mini- | Maxi-|Maxi-|Maxi-|,,,.,|Larva+| | mum. | mum.) mum.) mum.|mum. Total.) pupa, | Fupa- eu a | | : rt a ST TEST 2 i = ile sea es Days.| Days. | Days.| Days.| Days.| Days Days mere, Tero. 5. upust/31...... Ee ae SE See a ae Gab tas Te Ricca eae ing. Tex!) 2 September 3... .| Dame See gen fond be 19h 2346. | Sse ee oes Hallettsville, Tex...| August 30...... | 14 9 | 9 Sl aia Sees eit ees 6 VG gd Wy ae ee ee August 28, 29. ..| 10 | 9 9 5 | Gi lSee aka eo es hee It was impossible with a lens to find any characters to distinguish the larve of this species from any of the other chalcidoids, as all of the chalcidoid larve concerned in this report are finely, transversely lineolate and clad with a few hairs regularly placed in a line around the middle of each segment. The pupa is nearest in appearance to — that of Cerambycobius. The female pupa is robust, brown until almost mature, with no darker spots on the dorsal abdominal seg- ments, but with three longitudinal white lines and a transverse white line on each segment; the ovipositor is appressed to the dorsum and proportionately longer than in Cerambycobius. The exuvium is easily recognized by the form of the ovipositor and its brown color. (See figure of pupa and of chalcidoid larva, Pl. I, figs. 4, 7.) A .most interesting poimt in the biology of this parasite is the fact that a number of individuals were bred from Bracon cocoons. This is one of those phenomena which are here designated as accidental secondary parasitism—that is, where a natural primary parasite finds its host consumed by another parasite and in order to retain its hold on life is compelled to attack that parasite itself. 10292—Bul. 73—08——3 . 5 ; af : 34 PARASITES OF THE COTTON BOLL WEEVIL. The breeding records of the parasite are as follows: TABLE XXI.—Breeding records of a5 icrodontomerus anthonomi. Loe | As prima | As d Total. | PEMA: Secondary Locality: | ste: ? | parasites. parasites. | Male. Female. | Male. Female. | Male. Female. > aaa tei eee Rene feasted 1906. Poa S13 (eR he eee ie Ue re | AURORE SL oS ea ee ca iO fein aS as eet Sat ocean a eS SE 1 Golladi@ar pF Ce ae September 3... .2):....... ig gS a aD ae oe 1 Hallettsville, Tex.......... [eAUIRIEE AO. ee Pi eee | Y > ais tage Foe WisitoriDex iis Se es BUERSE 285: 5 tee ee ees | Bh ee ee AS ate ee eee soe DO ar Mee Sele ne August 29........ 2 : 3 1 3 1 Se ee Thirteen parasites were bred, of which 23 per cent were secondary. Owing to numerous expressions of incredulity concerning this dual parasitism it may be proper to state the proofs. In the first place, primary parasitism has been thoroughly established in the case of this species and also in the case of Eurytoma tylodermatis and Ceram- bycobius cyaniceps. Adults have been bred from larve which were actually observed to be feeding upon the weevil larve. The devel- opmental period of those adults bred precludes any arguments that they were bred from unobserved eggs of parasites on the larve. In the second place, the Bracon and chalcidoid larve are very easily distinguished, so that the notes in most cases stated whether the larva observed was a Bracon or a chalcidoid. In no case was one of the latter bred from a Bracon except when the Bracon cocoon was already formed at the time of the observation. F inally, secondary parasitism was proved because the parasites were actually bred from isolated Bracon cocoons, which were subsequently opened and from which the known exuvia of the secondary parasites were removed. 2. Eurytoma tylodermatis Ashm. This species was bred by Town- send in 1895 and by Mally during several years from the boll weevil. Ashmead described it as a parasite of Lyloderma foveolatum Say (Ashmead, 1896), a weevil breeding in the stems of Onagra biennis | and also in a species of Epilobium. It was reared by F. H. Chitten- | den from the larva of Tyloderma Foveolatum Say in stems of Onagra | biennis, September 23, from material collected at Rosslyn, Va. | This species was bred by the writer from Anthonomus disjunctus | Lec. breeding in the heads of Heterotheca subaxillaris at Jacksonville, ; Tex., October 13, 1905 (1 male); from Anthonomus squamosus Lec., breeding in the heads of Grindelia squarrosa nuda at Clarendon, Tex., ‘ September 22, 1905 (6 females), and September 26, 1905 (2 males) ; from Orthoris crotchii Lec. breeding in the seed pods of Mentzelia nuda at Clarendon, Tex., October 2, 1905 (1 male); and from Lizus mus- culus Say, which forms galls in the stems of Pol ygonum pennsylvani- cum, at Clarendon, Tex., October 2, 1905 (2 females), and October 17, 1905 (1 male). Mr. W. W. Yothers bred this Eurytoma from Lizus Bul. 73, Bureau of Entomotogy, U S. Dept. of Agriculture. PARASITES OF WEEVILS. Fic. 1.—Eurytoma tylodermatis, pupa. Fig. 2. bycobius cyaniceps, pupa. Fig. 4.—Microdontomert Bracon. Fig. 6.—Bracon mellitor, pupa. Fig. 7.— (Original. ) 1s anthonomt, pupa. Larva of chalcidoid. > (atolaceus incertus, pupa. PLATE |}, Fig. 3.—Ceram- Fig. 5.—Larva of Much enlarged. BIOLOGICAL NOTES ON THE PARASITES. 35 _ serobicollis, which breeds in great abundance in the stems of the com- mon road weeds Ambrosia trifida and A. psilostachya, at Victoria,Tex., April 5, 1905 (1 female). In a personal letter dated August 30, 1906, Dr. Wm. H. Ashmead writes of this species: ‘‘ Hurytoma tylodermatis Ashm. is another similar case [referring to his remarks on Ceramby- cobius, given later]. I have had several species of Eurytoma bred by Hopkins, Marlatt, ete., from beetles, and I can only quote their records. The genus seems to be primary and secondary as well as phytophagous, unless we can find characters to still further subdivide it generically.” This parasite is quite abundant throughout the season and is a con- tinuous breeder. The number of generations is probably little less than that of the weevil. There is but one individual to each host, and the latter may be in the larval or pupal state when attacked. The sexes are in the proportion of 29.1 per cent male and 70.9 per cent female. The females are very much larger than the males. Proceeding in the same manner as for the preceding species it is ascertained that the total developmental period is over 12 to 15 days, that the larval plus pupal period is over 11 to 14 days, and that the pupal period alone is at the minimum 6 days and maximum 13 days. Judging from this last period, for which the figures are definite, it may be safely said that the estimates for the larval and egg periods are very low. The increase in the length of the pupal period in October is noticeable. : The data upon the biology of Eurytoma tylodermatis are compara- tively continuous from July 18 to October 19. In studying the length of the various stages the same methods were used as outlined for Microdontomerus. The only stage which could be definitely limited as to the period of development was the pupal stage, which was found to last from 7 to 8 days in the latter half of July, 6 to 9 days during August, 7 to 9 days in September, and 11 to 13 days in October. The larve of Eurytoma were described in the notes as smooth, transversely lineolate, and with wrinklings at the sutures. The pup are white, pink-eyed, turning black toward maturity. They may be easily distinguished, by the lateral compression of the abdo- men and the straight venter, from the pup of Catolaccus with their dorso-ventral compression and obtusely angulated venter. The exuvium is cast in parts and is never found intact as in the case of the other chalcidoids studied; the remains are yellowish transparent. (See figure of pupa, Pl. I, fig. 1.) Secondary parasitism: One male was bred from material collected August 9 at Trinity, Tex., and two males from material collected September 19 at Waco, Tex., as secondary parasites in the cocoons of Bracon mellitor. In each case the cocoon was isolated when first 36 PARASITES OF THE COTTON BOLL WEEVIL. ee found, so that no doubt could be expressed as to the source of the parasites. Corroboration was obtained by examining the cocoons. | 3. Bruchophagus herrere Ashm. Considerable doubt has been raised by very eminent parasitologists as to the actual parasitism of the boll weevil by this species and some doubt has been raised concerning ~ its generic location. No subsequent corroboration has been obtained — to prove parasitism of the boll weevil. 4. Cerambycobius cyaniceps Ashm. The first published record of the parasitism of the boll weevil by this species is found in Mally’s Report (Mally, 1902), in which that writer states that he had bred it since 1899 at Austin, Tex. Only four records were obtained in previous years by the boll-weevil laboratory of the Bureau of Entomology; 1 female bred July 7 at Calvert, Tex., by G. H. Harris; 1 male and 1 female bred July 25 at Victoria, Tex., by W. E. Hinds, and 1 female bred March 11 at Corsicana, Tex., by C. M. Walker. Dr. F. H. Chittenden has reared it from-the larva of Tyloderma foveolatum breeding in the stems of Onagra biennis, September 11, from material collected at Chevy Chase, Md. He has also reared it from Bruchus exiguus Horn (Chittenden, 1893b). Ina personal letter dated August 30, 1906, Dr. Wm. H. Ashmead said of this species: ‘“‘Tt is not rare, has been bred from cerambycids and other beetles, and I have always supposed it to be a primary parasite. All of these beetles, however, have braconid parasites, and it may yet prove to be a secondary parasite as other of the eupelmines are said to be.” One female was bred by the writer October 17, 1905, as a probable parasite of Lixus musculus Say, breeding in stem galls of Polygonum pennsylvanicum collected September 19 at Clarendon, Tex. On Octo- ber 26, 1906, a female was bred from a Lixus musculus pupa collected in the same plant at Dallas, Tex., opposite the farm on which release experiments were conducted. On September 11 and 12, 1906, 2 females were bred from Anthonomus albopilosus breeding in seed of Croton engelmanni collected August 26, 1906, at Johnsons Bayou, La., by J. D. Mitchell. On October 30, 1906, 1 female was bred from Trichobaris tecana found breeding in stalks of Solanum rostratum by R. A. Cushman and the writer, along the road close to the plat upon which parasites were released at Dallas. This parasite is very abundant in eastern Texas, diminishing to the Southeast, and is entirely absent at Brownsville and through western Texas. It is a continuous breeder, attacking the weevil larve and pupe, one individual for each host. The sexes are in the proportion 19.7 per cent males and 80.3 per cent females. The females are several times longer than the males. The developmental periods for Cerambycobius cyaniceps have been worked out from data covering the period between July 12 and Octo- ber 4. The pupal period in July is 10 days or less, in August is from »~¥.) os . > 1 BIOLOGICAL NOTES ON THE PARASITES. 87 8 to 11 days, and in September from 9 to 12 days. During August it was ascertained that the entire developmental period exceeds 26 days. The larvee of Cerambycobius are described in the breeding notes as white, transversely lineolate, with a row of prominent hairs around the middle of each segment. The pup are elongate brown, with a short, obtuse, erect ovipositor, and with the dorsum of the abdomen marked with two dark spots on each segment. The brown exuvium is easily recognized from the ovipositor. The pupxe may be easily distinguished from those of Microdontomerus after a little practice. (See figure of pupa, PI. I, fig. 3.) Secondary parasitism: On September 14 a female Cerambyco- bius was bred from a larva which was found feeding on a Catolaccus pupa in material collected August 28 at Calvert. Although numer- ous cases of parasitism of Bracon mellitor were found, only 11.5 per cent of this species were secondary parasites. It was found as a secondary parasite on Bracon as follows: Beeville, Tex., July 12, 1 female. Corpus Christi, Tex., July 10, 1 female. Cuero, Tex., August 31, 1 female. Mansfield, La., August 24, 2 females. Trinity, Tex., August 9, 1 male, 1 female. Victoria, Tex., September 1, 1 female. Waco, Tex., August 28, 3 males, 10 females. Waco, Tex., September 19, 1 male, 2 females. In one case the attack of the Bracon is known to have been prior to spinning. : 5. Catolaccus wncertus Ashm. This species has been one of the most important species mentioned in the literature of the boll weevil. It was described as a primary parasite of Anthonomus signatus (Chittenden, 1893a). It was reared by F. H. Chittenden from A pion decoloratum Sm. breeding in Meibomia paniculata at Washington, D. C., from Apion griseum Sm. breeding in Phaseolus perennis at Washington, D.C., and from Bruchus exiquus (Chittenden, 1893b). Two females were bred by the writer October 16, 1905, from Antho- nomus disjunctus breeding in the heads of Heterotheca subaxillaris collected at Jacksonville, Tex. From Anthonomus eugeniw breeding in peppers at San Antonio, Tex., F.C. Pratt bred 3 females on October 18, 1905. From Anthonomus albopilosus breeding in the seed of Croton engelmanni at Johnsons Bayou, La., the writer bred 2 females on September 6, 1906, and from the same weevil breeding in Croton capitatus at Leesville, La., the writer bred 1 female on Sep- tember 29, and subsequently 3 females and 3 males. Catolaccus incertus is very common in all parts of the State and is well established as a boll weevil parasite. (See Plate III, #.) It is a continuous breeder, attacking the weevil larve and pup, one 38 PARASITES OF THE COTTON BOLL WEEVIL. individual for each host. The developmental period seems to be — considerably shorter than in either of the species preceding. ‘ The data upon which the following figures are based cover the period from June 25 to October 28. During June and July the total develop- mental period is known to be over 11 or 12 days, during August it is over 14 days, and during September and October over 18 days. The pupal period in June and July is only 4 to 6 days, in August 6 to 7 days, in September 5 to 9 days, .but in October 13 to 15 days. The larve of Catolaccus were described in the notes as having short hairs in a row on each segment. The pupe are white to yellow, the thorax turning black first as they approach maturity. The abdomen is very flat below and bent at an obtuse angle to the thorax. The head is very broad, and the eyes are pink. The exuvium is yellowish and resembles a little pomted cap. (See figure of pupa, AoE efice:-2:) 6. Sigalphus curculionis Fitch. No corroboration has been recorded of the parasitism of the boll weevil by this species. This parasite is very commonly bred from the plum curculio (Conotrachelus nenu- phar Hbst.). Chittenden also records it as a primary parasite of Trichobaris trinotata Say, which breeds in the stems of Solanum rostratum (Chittenden, 1902). | 7. Urosigalphus anthonoma Cwfd. This parasite was again bred September 20 from material collected September 5 at Brownsville. The period in the cocoon was at least 9 days. The cocoon with weevil larva’s head attached was half in a cotton seed in a boll. It was very much finer meshed than that of Bracon mellitor and easily broken. In addition to this species and (8) Urosigalphus schwarzi Cwfd., both bred from Anthonomus grandis, Urosigalphus armatus Ashi. has been bred from Balaninus, and another species ( Urosigalphus bruchit Cwfd.) from Bruchus prosopis Lec. taken at Harlingen, Tex., in beans of Prosopis glandulosa. Hence it is very probable that the species of this genus are normally weevil parasites. 9,10. Bracon mellitor Say. Bracon dorsator Say. Bracon xantho- stigma Cress. These are all forms aft a single very variable species, of which the entirely red form holds the name B. mellitor, that with black sternum and metathorax the name B. xanthostigma, and that with the thorax almost entirely black and the vertex of the head also black, being also smaller in size, has been known as B. dorsator. A peculiar record is furnished by F. H. Chittenden who reared this species from the strawberry leaf-roller Ancylis (Phoxopteris) comp- tana Fr6l., from material collected at Cabin John, Md., July 9, 1899. In a personal letter dated August 30, 1906, Dr. Wm. H. Ash- mead writes: ‘‘ Bracon mellitor Say is undoubtedly a most important parasite, widely distributed in the United States, and must affect —s BIOLOGICAL NOTES ON THE PARASITES. 39 - very ged different beetles, although usually rhynchophorous beetles.”’ . The typical form has been bred from Anthonomus grandis at all times and in all places between June 15 and October 4. The form xanthostigma has only been bred from the boll weevil between Sep- tember 16 and April 28, while dorsator was bred August 2, 1903, at Victoria; November 20, 1895, at Goliad, and December 17, 1895, at Beeville. B. mellitor was bred June 19, 1905, at Dallas by W. W. Yothers from Anthonomus fulvus Lec., which breeds in the buds of Callirrhoe involucrata, and on June 14 he bred dorsator from the same weevil. On September 20, 1905, F. C. Pratt bred male and female dorsator and female mellitor from Desmoris scapalis Lec., breeding in the flower heads of Sideranthus rubiginosus at Mexia, Tox 5 on Sep- tember 23 he bred the typical form from the same weevil collected at Calvert, Tex.; on September 29 both the typical form and dorsator from Mexia material; and on October 27 he again bred the typical form from Mexia material. On September 30, 1905, the writer bred mellitor and xanthostigma from Anthonomus squamosus Lec., ie in the heads of Grndelia squarrosa nuda at Clarendon, Tex.; on October 2, 4 of the typical form and 1 xanthostigma were aah October 3, 3 typical, and finally on October 16 a xanthostigma, were bred. On October 18 and 23 dorsator was bred by F. C. Pratt from Anthonomus eugenii Cano, breeding in peppers at San Antonio, Tex. On September 6, 1906, J. D. Mitchell bred a typical form from Antho- OES ae pawis ees peeveine in seed of Croton camtatus at Victoria, Tex. The data upon the life-cycle of Bracon mellitor cover the period from June 25 to November 15. The entire developmental period covers at least 21 days in June and 33 in October, but probably con- siderably more. The period within the cocoon has been limited to between 5 and 6 days in June, to 7 days in July, 6 to 11 days in August, 3 to 7 days in September, and 15 to 27 days in October. The minimum of 3 days in September is based upon an observa- tion of the spinning of the cocoon and the time of maturity, and the record of 5 days in June was obtained in the same manner. The larve of Bracon can be immediately separated by the absence of hairs and by the body being punctate instead of lineolate. The pup are yellowish, loosely constructed, with the appendages very fragile and inclosed in a stout one-meshed silken cocoon, which varies from pure white to golden yellow or dark brown. In several cases where particular note was made of the brown color of the cocoon hyperparasites were bred, but this was not a constant indication. The species varied greatly in size, depending upon the amount of food available. (See figures of larva and pupa, PI. I, figs. 5, 6.) 40 - PARASITES OF THE COTTON BOLL WEEVIL. No dark forms of this species were bred until September 10, 1906, except a single B. dorsator which was bred from Cuero material col- lected August 31. The rest were all bred from material collected at Brownsville, September 29; Dallas, October 2, 6, 10; and Waco, October 12. The record of all Bracon bred after October 10 is as follows: October 10, Bracon mellitor, 3 males, 5 females. 11, Do. 1 male. 12: Do. 1 male. Bf Do. 1 female; mellitor xanthostigma, 2 females. 15, Do. 1 female. 18, Bracon mellitor xanthostigma, 3 females. 20, Do. 2 females. 22, Bracon mellitor, 3 females; mellitor zanthostigma, 2 females; mel- litor dorsator, 2 males, 1 female. 24, Bracon m. zanthostigma, 1 female. 25, Do. 2 females; m. dorsator, 1 female. ok: Do. 2 females. November 1, Do. 3 females; m. dorsator, 1 male. 5, Doss 1 female. 6, Bracon mellitor dorsator, 1 female. 14, Bracon mellitor canthostigma, 1 female. 11. An undetermined braconid of the size of Bracon mellitor, but with the base of the abdomen black and belonging to a different sub- family, was bred September 17 from a yellow cocoon in a fallen square collected at Victoria, Tex., September 1. Unfortunately this was lost in the mails. 12. Myiophasia «enea Wied. This species is recorded as a parasite of Balaninus nasicus Say, Chalcodermus sp., Conotrachelus juglandis Lec., and Sphenophorus parvulus Gyll. (Coquillett, 1897), and also of Ampeloglypter sesostris Lec. (Aldrich, 1905). One specimen was bred July 6 by the writer from a larva of Conotrachelus affinis Boh. found in a hickory nut collected June 8 at Logansport, La. As parasites of the boll weevil from fallen squares collected at Many, La., August 23, 1 male was bred September 5 and 1 female September 8, while 1 failed to mature. From a hanging square collected at Waco, Tex., August 29, a puparium was obtained but the fly not bred. From a small boll collected at Victoria, Tex., July 12, a deformed fly was bred. Parasitism by this species can always be positively proved if the puparium is found, as it is inside of the stretched skin of the weevil larva. The affected larva is of a tawny parchment color and shows the projections of the appendages of the fly puparium. The developmental period is undoubtedly in excess of 28 days, as shown by the first record above. 13. Several attempts have been made to introduce Pediculoides ventricosus Newp. into Texas as a parasite of the boll weevil, but BIOLOGICAL NOTES ON THE PARASITES. 41 with no success. Much has been written upon this mite by Professor Herrera and his staff. 14. There are, however, native mites, including Tyroglyphus ka breviceps Banks (Banks, 1906, p. 17), eh in some Cases are a con- siderable factor in the Bespoaciion of the immature weevils. At ~ Calvert, Tex., in moist fallen squares collected September 13, 11 out of 18 cases of parasitism were mites. 7. breviceps was described from Victoria. 15. Hydnocera pubescens Lec. This clerid was found to be pre- daceous in its larval stage upon the boll weevil and all of its parasites. The egg is probably inserted into the cell of the weevil, and the young predator immediately starts its attack, consuming whatever it finds in the way of insects, and finally spins a loosely meshed, single-layer, silken cocoon, and pupates therein. From data of mate- rial collected at Waco, Tex., August 28, an approximation of the developmental periods was obtained. The longest period from col- lection to spinning was 34 days, the period in the cocoon was 12 days, the adult being formed 3 days before leaving the cocoon. In order to prove the predaceous habit live weevil pupe were fur- nished individual clerid larve, and in most cases were completely consumed. In several cases large larve were found in Bracon cocoons which were punctured with holes large enough only for the very smallest of the larve. | 16. In a number of cases, material collected at Victoria, Dallas, and Brownsville gave evidence of a predaceous attack upon weevil } stages by Cathartus cassix Reiche. IV: THE SOURCES OF THE PARASITES. In the preceding sections it has been pointed out that the para- sites of Anthonomus grandis are also common to various other spe- cies of weevils. There is a more or less clearly defined theory in parasitology that the parasites of a particular genus or tribe are con- fined to the insects of a particular family or order. With this idea in mind a list of the known parasites of the Rhynchophora has been compiled, in order to show the characteristic groups and the possible sources of boll-weevil parasites. PARASITES KNOWN TO ATTACK RHYNCHOPHORA. Parasite. Host. Fungi. TLS SCS aE re Anthonomus grandis Boh. Lo Se ae Anthonomus grandis Boh. Empusa (Entomophthora) sphxrosperma..Phytonomus punctatus Fab. Entomophthora phytonomi.....-..-.----- Phytonomus punctatus Fab. Sporotrichum globuliferum ...........--- Epicerus imbricatus Say. 42 PARASITES OF THE COTTON BOLL WEEVIL. Parasite. - Host. Acarina. Tarsonemide. . Pediculoides ventricosus Newp ...--.----- Anthonomus eugenii Cano. Anthonomus grandis Boh. Tyroglyphidee. Tyroglyphus breviceps Banks .........---4 Anthonomus grandis Boh. eo) et ee pe ee eek Le ab tee Selo Anthonomus eugenit Cano. Diptera. Dexiide. Metadeom Dasalig 3G a) oe ee ae fee Conotrachelus juglandis Lec. Tachinide. Myophasia tenea Wied... - 2222-2522 22 21 Ampeloglypter sesostris Lec. Anthonomus grandis Boh. Balaninus nasicus Say. Chalcodermus exneus Boh. Conotrachelus affinis Boh. Conotrachelus juglandis Lec. Sphenophorus parvulus Gyll. Myiophasia robusta Coq.....------.-..:- Sphenophorus robustus Horn. Hymenoptera. Proctotrypoidea. Platygasteride. Platygasterine. ‘ Trichacts rufipes Ashm.................-?Balaninus nasicus Say. Chalcidoidea. Torymidz. Monodontomerine. Microdontomerus anthonomi Cwid......- Anthonomus grandis Boh. Brachytarsus alternatus Say. Eurytomide. Eurytomini. Eurytoma magdalidis Ashm .......-.----- Magdalis armicollis Say. Eurytoma tylodermatis Ashm .........---2 Anthonomus disjunctus Lec. Anthonomus grandis Boh. Anthonomus squamosus Lec. Apion segnipes.4 Lixvus musculus Say. Lizxus scrobicollis Boh. Orthoris crotchii Lec. Tyloderma foveolatum Say. Bruchophagus herrere Ashm.........----2 Anthonomus grandis Boh. Cleonymidee. Cleonymine. Chemropachys colonise Leet eee Magdalis xnescens Lec. Encyrtide. Eupelminz. Eupel- mini. Cerambycobius cyaniceps Ashm ........-- Anthonomus grandis Boh. Anthonomus albopilosus Dietz. Bruchus exiguus Horn. Lixzus musculus Say. Trichobaris texana Lec. Tyloderma foveolatum Say.@ Pteromalidz. Pteromaline. Meta- ponini. ¢ Bruchobius laticollis Ashm ............-- Bruchus pisorum L. Pteromalide. Pteromalinz. Rhaph- itelini. @On the authority of F. H. Chittenden. ee een .? ¢ ry ro j urtack PRT ROSUEHOEL. oa Paras Host. Shale Betiies—Continied. OM Ue toa 2 ee Magdalis xnescens Lec. - Pteromalidee Pteromaline. Ptero- malini. ‘Catolaccus anthonomi Ashm.........-.-- Anthonomus signatus Say. Catolaccus celiodis Ashm..............-- Acanthoscelis acephalus Say. Catolactus incertus Ashm .............. .2 Anthonomus xneolus Dietz. Anthonomus eugenti Cano. Anthonomus albopilosus Dietz. Anthonomus disjunctus Lec. Anthonomus fulvus Lec. Anthonomus grandis Boh. Anthonomus nigrinus Boh. Anthonomus signatus Say. Apion decoloratum Sm. @ Apion griseum Sm. @ Auletes tenuipes Lee. Bruchus exiguus Horn. Zyqgobaris xanthoxyli Pierce. Neocatolaccus tylodermz Ashm......-..--. Lixus parcus Lec. Lixus musculus Say. Tyloderma foveolatum Say. Pteromalide. Spalangiine. Cerocephala pityophthori Ashm .......-.- Pityophthorus consimilis Lec, Cerocephala scolytivora Ashm..........--/ \ seolytid. Eulophide. Entedonine. Om- phalini. Omphale linda Ashm................--- . Ceutorhynchus rapx Gyll. Eulophide. Entedonine. Ente- donini. Asecodes albitarsis Ashm..........--..-- Magdalis xnescens Lec. Entedon lithocolletidis Ashm .....--...--- Anthonomus nigrinus Boh. Eulophide. Tetrastichine. Te- trastichini. . LTE Sy ES Ea Orthoris crotchii Lec. Mymaride. Mymarine. Ana- phini (egg parasites). Anaphes conotracheli Girault .........--- Conotrachelus nenuphar Hbst. Ichneumonoidea. Ichneumonide. Ophioninee. Pori- zonini. Porizon conotracheli Riley...........-.- Conotrachelus nenuphar Herbst. Braconide. Blacinz. Calyptini.— Calyptus tibiator Cress........-.--.-----2 Anthonom us signatus Say. Braconide. Sigalphine. Sigalphus canadensis Prov...........-.- Anthonomus scutellatus Gyll. Podapion gallicola Riley.» Sigalphus copturi Riley ms.......-.---- Cylindrocopturus longulus Lec.» Conotrachelus eens Boh. aQOn the Wedionity of F. H. Chittenden. b Breed together. 44 PARASITES OF THE COTTON BOLL WEEVIL. Parasite. Host. Ichneumonoidea—Continued. Sigalphus curculionis Fitch.......-..-.-. Anthonomus grandis Boh. Conotrachelus juglandis? in nuts. Conotrachelus nenuphar Hbst. Trichobaris trinotata Say. Sigal pnus apes foe eet ake ake eee Chalcodermus #xneus Boh. Sigalphus zygobaridis Cwid......-.-.--- Zygobaris xanthoxyli Pierce. Urosigalphus anthonomi Cwid........-- Anthonomus grandis Boh. (Texas). Urosigalphus armatus Ashm.....-.--..--- Balaninus spp., Conotrachelus spp. Urosigalphus bruchi Cwid.....-...-..--- Bruchus prosopis Lec. Urosigalphus schwarzi Cwid...........-- Anthonomus grandis Boh. (Guatemala). Braconide. Chelonine. Phanerotoma tibialis Hald..-..: 5.2.2. atl eae nigrinus Boh. Braconidee. Agathidinze. Micro- dini. Microdus simillimus Cress....--...----- Lizus scrobicollis Boh. Braconide. Braconinz. Braco- nini. Glyptomorpha liai Ashm......-..---.--- Lizxus scrobicollis Boh. Glyptomorpha mavaritus Cress......-.-- Lixus scrobicollis Boh. Glyptomorpha novitus Cress.....-.------ Tivus musculus Say. Glyptomorpha rugator Say..-.-..-------- LTixus concavus Say. Lixus musculus Say. Vepro;belfrage: Cress sees LTizus scrobicollis Boh. Melanobracon simplex Cress-.....---- _..-Dendroctonus picexperda Hopk. Microbracon nuperus Cress....-..----.--- Orthoris crotchii Lec. '‘Bracon-analeus Ashi 2. . ses. S52 see Tyloderma fragarix Riley. ibracon-anthonomi-Ashm. 02. * 222) ee Anthonomus signatus Say. ETOCON= MELLLOT SAY © oho ons elo ote ee Anthonomus eugenii Cano. Anthonomus albopilosus Dietz. Anthonomus fulvus Lec. Anthonomus grandis Boh. Anthonomus squamosus Lec. Desmoris scapalis Lec. IBFacon, issodis Ashwin A ~ eee enee Pissodes strobi Peck. Bracon rhyssematt Ashm. ms.......----- Rhyssematus lineaticollis Say. Bracon smicronygis Ashm. ms.....--.---- Smicronyx tychoides Lec. ! IBLACON ASD 2 2 io ee eee ee ee Tomicus pini Say. | IBLOCON "Bo an Sonne oe oh a A eee ee Brachytarsus limbatus Say. | BEACON BD <= 2c Cae eee See eee Baris sp. | Braconide. Rhogadinze. Rhyssa- lini. Rhyssalus pityophthori Ashm......-..---- Pityophthorus sp. Braconide. Spathiinse. Spathiini. Spathius canadensis Ashm........------ Dryoceetes autographus Ratz. (?) Maadalis olyra. Phlwosinus graniger Chap. Tomicus sp. BIOLOGIES OF THE WEEVILS CONTRIBUTING PARASITES. ( It is of considerable importance in framing means of combating the boll weevil with parasites that the weevils usually found in the vicinity of cotton fields should be thoroughly known. In order that _-—~—s BIOLOGIES OF WEEVILS CONTRIBUTING PARASITES. 45 he conclusions in this regard may be more thoroughly understood, | this subject must be introduced by a series of brief biologies of all. | the weevil species which have contributed parasites to the attack of | - the boll weevil. ‘. =: CURCULIONID®. APIONINZ. | ps 1. Apion decoloratum Sm. breeds in Meibomia paniculata. It is | parasitized at Washington, D. C., by Catolaccus incertus. 2. Apion griseum Sm. breeds in Phaseolus perennis, and is para- _ sitized by the same species as the preceding. CURCULIONIN:. CLEONINI. 3. Livus musculus Say makes a gall in the stems of Polygonum pennsylvanicum. The larve and pupe are found in these galls. The weevil and its host plant are typical of tne fall, the plant being found in low moist ground, frequently in close proximity to cotton fields. The weevil is attacked by two of the important boll-weevil parasites. 4. Llixus scrobicolis Say dwells in the stems of Ambrosia trifida and psilostachya, two of the commonest roadside and waste-place weeds throughout the country in summer and fall. The entire stem is riddled by the weevil larve, which pupate in cells of frass at the end of their burrows. Lurytoma tylodermatis and other parasites not concerned in the discussion have been bred from this weevil. ERIRHININI. 5. Desmoris scapalis Lec. breeds in the seed heads of Sideranthus rubiginosus, a summer weed, which is very abundant in some localities along roadsides and on prairies. The larve are expelled with the seed and enter the ground for pupation, maturing in the following spring. This species is parasitized by Bracon mellitor, which has a much more rapid development than its host. (See Pl. III, 6, D, F,G.) ANTHONOMINI. 6. Anthonomus (Anthonomorphus) fulvus Lec. breeds in the buds of Callirrhoe involucrata, an early spring mallow, which is common in May and June on moist meadows. The larve feed upon the floral column of the bud or the imperfectly opened flower and pupate in a cell of excreta in the capsule or fallen corolla. Bracon mellitor and Catolaccus incertus have been bred from it. (See PI. II.) 7. Anthonomus signatus Say, the strawberry weevil, breeds in a number of rosaceous plants, such as strawberry, blackberry, raspberry, and wild yose, as also in red-bud. It is an early spring weevil, ovi- positing in the buds, which soon drop to the ground, where the larva transforms to the pupastage. It is parasitized by Catolaccus incertus. 46 PARASITES OF THE COTTON BOLL WEEVIL. 8. Anthonomus nigrinus Say is an eastern weevil which breeds in the buds of Solanum carolinense and various other solanaceous plants, occurring principally in the spring and early summer, but not con- fined to one generation. It oviposits in the buds, causing them to fall. The larva makes its cell in the center of the bud through the pistil and all of the stamens and pupates in this cell. It is a host of Catolaccus vncertus. 9. Anthonomus albopilosus Dietz is a fall species which breeds in the seed of Croton capitatus and C. engelmanni, weeds which are very abundant in pastures. The larve eat out one seed and then enter a second and form their pupal cell in this. The weevil serves as a host to Cerambycobius cyaniceps, Catolaccus incertus, and Bracon mellitor. 10. Anthonomus x#neolus Dietz is a spring species which breeds in the buds of Solanum torreyi, S. rostratum, and S. eleagnifolium. The larvee feed within one or two anthers, in the latter case forming a cell which cements the two together. Im many cases the flower does not fall, and is able to fruit. The weevil is a host of Catolaccus incertus. 11. Anthonomus eugenii Cano (xneotinctus Champ.), the pepper weevil, is a recent introduction from Mexico. It is a fall species, which breeds in the interior of the cultivated peppers. (See Plate III; A, (.) Itisa host to Catolaccus incertus, Bracon mellitor, and Pedi- culoides ventricosus, as determined by Professor Herrera. Anthonomus mexicanus Boh., another pepper weevil, is very likely identical. 12. Anthonomus squamosus Lec. breeds in the heads of Grindelia squarrosa, a fall plains plant, which is very abundant in semiarid Texas. The weevil larva makes a cell among the seed, which is formed of the hardened gum of the flower and excreta. It has probably only one generation. It is very highly parasitized and principally by Bracon mellitor and EHurytoma tylodermatis. 13. Anthonomus disjunctus Lec. breeds in the heads of Heterotheca subaxillaris, a fall plant, which is very abundant along roads, waste places, and on meadows. The weevil larva makes a small cell, formed of the hardened gum and excreta of the weevil, among the seed. There is but one generation. Hurytoma tylodermatis and Catolaccus incertus have both been bred from this weevil. CRYPTORHYNCHINI. 14. Conotrachelus affinis Boh., the hickory nut weevil, has been found to be the host of Myiophasia xnea. It is an early summer weevil. Pupation is in the ground. 15. Conotrachelus nenuphar Herbst, the plum and peach curculio, breeds in the fleshy part of the fruit and pupates in the ground. It is the host of Sigalphus curculionis, which has once been bred from Anthonomus grandis. | Bul. 73, Bureau of Entomology, U. S. Dept. of Agriculture PLATE Il. THE PURPLE MALLOW (CALLIRHOE INVOLUCRATA), A Foop PLANT OF Two WEEVILS RELATED TO THE BOLL WEEVIL. Fig. A.—The buds and flowers. which are subject to attack by Anthonomus fulvus, and the capsule, subject to attack of Macrorhoptus estriatus. Fig. B.—Bud infested by Anthonomus fulvus, Fig. C.—Flower injured by adult weevil of Anthonomus fulvus. (Original. ) Bul. 73, Bureau of Entomology, U. S. Dept. of Agriculture Fig. A.—Pepper, showing egg pu rubiginosus, showing cell of Desmo ( Pepper, showing larva of Antho mus eugeniiin situ Fig. D Head of Sid: t}; is SEH in itseell. Fig. E.—Section of of primary parasite Catolaccus incertus ore ethan Vey ST AnGCEEH Fig. G.—Desmoris scapal ae. aoc ipalis. adult weevil Origina Bae OTOIES OF WEEVILS CONTRIBUTING PARASITES. 47 | 16 . Chaleodermus zneus Boh. is the cowpea-pod weevil, although i once been bred from a cotton square. It is docaried as a es x Da ehasia ened. 17. Tyloderma “foveolatum Say breeds in the stems of Onagra _biennis, an early summer evening primrose. Pupation takes place in the larval burrow. It is parasitized by Lurytoma tylodermatis and ~— Cerambycobius cyaniceps. CEUTORHYNCHINI. : 18. Auletes tenuipes Lec. This species was found to breed in the _ buds of Galpinsia hartwegi at Dallas in the spring. The larve feed ‘ within a single anther in the bud, leaving it when the flower opens and entering the ground for nupation. The entire life cycle does not ~ exceed 25 days, of which 11 days only is spent in the bud. Catolaccus incertus has been bred. as a parasite. BARINI. 19. Orthoris crotchii Lec. is a very abundant fall weevil in western Texas, breeding in the seed pods of Mentzelia nuda, a plains plant. Pupation is in a cell formed within several seeds. The species is highly parasitized by several species, the least of which, however, is Eurytoma tylodermatis. 20. Trichobaris tecana Lec. is a stalk weevil, breeding in the stems of Solanum rostratum, a plant common in waste places in the summer and fall. The weevil cells are not more than an incl: apart through- out the stem. Cerambycobius cyaniceps has been bred as a parasite. 21. Trichobaris trinotata Say, the potato stalk weevil, is another host of Sigalphus curculionis. 22. Ampeloglypter sesostris Lec. is a grapevine weevil, and a host of Myiophasia xnea. It is not recorded from Texas. 23. Zygobaris xanthoryli Pierce. This new species breeds in the berries of Xanthoxylum at Runge and Beeville, Tex., in the spring. _ The larve feed in the interior of the seed until the seed is thrown to the ground. They then enter the soil and pupate in a tiny earthen cell, being in the ground about a month. Catolaccus incertus has been bred as a parasite. ANTHRIBID 4. 24. Brachytarsus alternatus Say breeds in the stems of Sideranthus rubiginosus. It is a constant breeder, entirely riddling the stems. Microdontomerus has been bred from it. BRUCHID 4. Although not considered Rhynchophora by American writers, it is very probable that the Bruchide are a connecting link between the Anthribide and Chrysomelide. 48 PARASITES OF THE COTTON BOLL WEEVIL. 25. Bruchus exiguus Horn breeds in the seed pods of Amorpha fruticosa in the fall. It is a host of Cerambycobius cyaniceps and Catolaccus incertus. It is noticeable from the foregoing that Bracon mellitor attacks bud, flower, pod, and seed weevils; Catolaccus incertus attacks bud, pod, and seed weevils; Cerambycobius cyaniceps attacks bud, pod, and seed, but mainly stem weevils; Eurytoma tylodermatis attacks bud, flower, pod, and stem weevils; Microdontomerus anthonomi attacks bud, capsule, and stem weevils; Myiophasia xnea attacks bud, fruit, pod, nut, and stem weevils, and Sigalphus curculionis attacks bud, fruit, pod, and stem weevils. Such general habits indicate a generaliza- tion of habit in the species concerned and give promise of the possibility of more extensive adaptation to the boll weevil as a host. ROTATION OF HOSTS. The most important item in the solution of the parasite question is probably concerned with the treatment of the other hosts. It is found that the parasites which now attack the weevil are naturally parasitic on weevils of short season and few generations, and the most feasible proposition is that of forcing them to attack the boll weevil only. Two lines of action are suggested as possible and practicable. The first is, that such plants as the Crotons, hosts of Anthonomus albopilogus, might ‘be planted in abundance in the pastures because they make good feed and are easily destroyed, and that thus the weevils and their parasites would increase in great numbers and the latter might perhaps attack the boll weevil. The counter proposal is that the timely elimination of the summer series of host plants would cut off the possibility of finding any host but the boll weevil, which would be in abundance. The cutting of the weeds around the fields could not result disadvantageously, as there are numerous pests harbored by these same weeds. At present the information as to the rotation of hosts is incomplete, and it is therefore necessary to go very fully into this question as well as to test both methods which have been suggested. The known hosts of Bracon mellitor would insure it an uninter- rupted rotation if they all occurred in a given locality. They do not, so there are still other unfound hosts of this species. The season of its hosts as far as known are as follows: Anthonomus fulwus breeds from May 3 to July 12. Desmoris scapalis breeds from July 25 to September 22. Anthonomus squamosus breeds from August 11 to September 19. Anthonomus albopilosus breeds from August 26 to September 29. Anthonomus eugenii breeds from October 6 to October 31. ‘ c ROTATION OF HOSTS. 49 Anthonomus signatus breeds from April 11 to June 12. Anthonomus fulvus breeds from May 3 to July 12. Auletes tenwipes breeds from May 9 to May 25. Zygobaris xanthoxyli breeds from May 11 to June 29. Anthonomus xneolus breeds from May 17 to July 12. Anthonomus nigrinus breeds from June 30 to July 18. Anthonomus albopilosus breeds from August 26 to September 29. Anthonomus eugenii breeds from October 6 to October 31. Anthonomus disjunctus was found breeding October 11 to 14. The known habits of the hosts of Cerambycobius cyaniceps are as follows: Tyloderma foveolatum breeds from June 22 to September 23. Trichobaris texana breeds from June 26 to October 11. Lixus musculus breeds from August 11 to September 19. Anthonomus albopilosus breeds from August 26 to September 29. The following data comprise all that is known of the hosts of Eurytoma tylodermatis: Tyloderma foveolatum breeds from June 22 to September 23. Lixus scrobicollis breeds from July 12 to April 17 (following year). Anthonomus squamosus breeds from August 11 to September 19. Orthoris crotchti breeds from August 11 to September 19. Lixus musculus breeds from August 11 to September 19. Anthonomus disjunctus was found breeding October 11 to 14. In the field at Dallas upon which release experiments were con- ducted, and in a series of five fields in various directions from Waco, it was found that the various species of parasites were exceedingly | localized, indicating that the parasites were derived from the imme- diate vicinity. On the Dallas field, by reference to the tables given in Section IT, it will be noticed that Plat B with one small exception was the only plat in which Catolaccus was found; that Plat B was the only one from which Cerambycobius was bred; that Eurytoma was not found in Plat C, but was predominant on Plat EK; and, finally, that - Bracon was well distributed. At Waco on all five fields Bracon Wien was present in the pro- portion of 20-to 50 per cent. On the prairie land field, surrounded only by Ambrosia, Helianthus, and Xanthium, 41.6 per cent of the parasites were Hurytoma tylodermatis. On the other fields, which were on the bottoms, only one Eurytoma was taken to a field. Cato- laccus incertus was present on the prairie land field and one bottom land field. Cerambycobius was present in all the bottom lands and very numerous, 58.3 per cent, in a field which had considerable Solanum rostratum about it; it was entirely absent on the prairie. The commonest plants on the bottoms were Heterotheca subazillaris, Croton spp., Solanum spp., and Xanthium. 10292—Bul. 73—08——-4 50 PARASITES OF THE COTTON BOLL WEEVIL. V. CONCLUSIONS AND PROSPECTS. In conclusion the writer would say that there are a number of very important points obtained which indicate a possible natural control of the boll weevil. The actual combinations of conditions which bring about the instances of high parasitism can not be understood. It is very evident that the elements in the combination are relative moisture and light, plant response to weevil injury, abundance of other species of weevils in the immediate vicinity, and, finally, the ability for rapid adjustment to new host relations possessed by the local parasites. Very high parasitism has been found, and it may therefore be expected again, perhaps locally, perhaps regionally. It may not necessarily be expected two years in succession at the same place, for a change in cultivation, an eradication of certain surrounding plants, or various other conditions might destroy the advantages pre- viously gained. On the other hand, these same agencies in another locality might attain the opposite result. Release of parasites in the open field on a small scale has been found to increase the rate of parasitization. This will be tried on a more extensive and better planned outline another year. The abundance of hosts which have parasites in common with the weevil and the fact that parasitization takes place in the first genera- tion give promise that the weevil’s advance may be constantly dis- puted by the parasites. BIBLIOGRAPHY. — Aupricu, J. M. ' 1905. Catalogue of North American Diptera. <2 ee mn sce c ccs asecee 43 PSF lL | II 2I I: i RUS Se 46 Fos Sun ase Sl ori treat Rio) ) ie 46 ECE UMM PROC LIOM sagt me ate eee aca - win owe ee we eee ok 48, 49 AGN ROLPAOCOIU MICULILOT =e) he ok ce oe ee ee ee wee 39, 44 Gatalacows ineertus. 2.2 Ooo le ca we ee lee cee 37, 43 GerambYCODULS CYOMACEDS =... 22 es ee a 36, 42 PAM OT UP ITRCO ILEUS: a te cieiade ooo 4 a die eS wo ew eee 37, 39 LRLE ELAR AG ORO) gp hel a 36-37 ASST ROVT Sich ae sete ho al 4-5, 48 ME OLOP ICH NOLES = - 22 cae cic ove ee eb see eee cee e ee 46 {die BBO Sey 11s) Oye ai aa te a ee 49 MBSTHOD CC OUOLOCCUSIINICETIUS. .. so ac eee oe ene ee ee oe 37, 43 EMULOMMUYLOUCTININIS = 26. oon. e oo oe ee ee ee 34, 42 . in Heterotheca subawillaris...............-------++---- 34, 37 e eugenti, A. xneotinctus a SynonyMm..............--..2.220-2-6--- 46 : PMCs ee 46 PE MITCLURT OU ret cane ano 38 oss Bee a oeloe eee 48, 49 ORINOU AATEC OTIINCIWON —— to nae Sw as eins a oe eee eee 44 HOVE AOTSOLOT = 6a pikas cree ee 39 WRLOIGCCUS INCELUUS. — 2 wiscoa0caces e-e one nec cee 37, 43 PZCHUCULOUAES: DETUPUCOSUS 0 =e o> snot d sees cae 42 PE UGLINDILSHOEUICE DS anon, nae em ORS att ae 42 NPTCR ELS ee tera ioe = ier eee ha ees Cs che Bere reer 37, 39 RPE IC ASM OLCB eae iret S so Sa ee aie aie eet e ecient a wke cake ae 45 breeding period........... av ase ia a PE a Pee are 48, 49 STOLE TICON, MIELIWMOT s oo oo oon eee e abe veins soc ccis cee un cUmeOy eee HORT GOT SUI ot bao Westone oe mie ee 39 BAMTUCCUS UICETTAG Ce. waoctee 22.8 we Oe ae pn ete ee 43 MMU AINITLNOL URUOIUCTOUE o's x2 3s Seo whe aoc es be we eee 39 grandis (see also Boll weevil). . > > 54 PARASITES OF THE COTTON BOLL WEEVIL. . Page. Anthonomus grandis, host of Aspergillus sp... .-. =. o222 222+. ieee eee 41 BIACONIG 2s 25 3 ee ee ee eee 29, 40 Bracon Wenge «ote c toon an VO ee t4 and its Torms.: i. <02 5.220 -eeee se 39 Bruchophagus herrerg®:.. 72. 3-3 ee ee eee 42 Catolaccus incerta 2 eno) ae 43 Cerambycobius cyaniceps ......-.------- 2 eee eee 42 Cordycéps sp; - coe eee eee. eee 41 Eurytoma tylodermatis. . =v tee eee ee 42 Microdontomerus anthonomi .............-------- 28, 42 Miylophasia net.) 2 ee ee ee 42 Pediculordes ventricosus & 2. ee 42 Sigalphis Cumeunonis 2 ee ee 44, 46 Tyroglyphus: breviceps. lee eo. ee eee 42 Urosigalphus anthonomt =. ::-2---2 05-22) ee ee 38, 44 SCHWOTZT. oie no Neo oe ee 38, 44 possibly a host of Catolaccus anthonomi.......-.-...----- 31 mexicanus probably — A> eugeni =o. ee ee ee eee 46 nigrinus, bibliographic reference “7. 2222) es eee ee ee 51 biological notes: 2.222232 ee ee ee 46 breeding period: .22: Sve. S eo eee ee eee 49 host ‘ef Catolaccus anecrius_- 9s. =a eee ee 43 5 iniedon hithocollehidns 90". ee ee 43 Phanerotoma, tibialis 222 ee ee ee 44 scutellatus; host ‘of Sigalphus canadensis:2.-=:--.- 2222-2 22 -e eee 43 signatus; bibliographic reference 222 =- 2-2 -e- e eeee 51 Dbiological:notes\-. 2.2.24. .805 5 eee ee ee 45 breeding, period. ue oe ee ee ee eee 49 5 host of Bracon anthonont-=.2 se. 9 no ee 44 Calyptus tibiator.......- eS eee eda Sk 43 Catolaccus anthonomi: 2) = oGod sere INCENTUS Ss So RE ee ee 37, 43 squamosus, biolopical' notes. (2252222 5-2- ee =e eee eee 46 breeding period: 220 ee ee ee 48, 49 host of Bracon. melittor—-. sack 2 oe eee 39, 44 form zanthostigma.......-..---- 39 Eurytoma tylodermatis 222222223 ee ee 34, 42 in Grindelia:squarrosa nuda, 22.22.9285 8 oe 34, 39 Ant. (See Solenopsis geminata.) ‘Apion decoloratum, biolozical notes: =* 5-2... . 2. so. e ee eee 2 eee 45 host of Catolaceusincertus:..% =: 225222 ee 37, 43 in Meibomia- paniculata. 20) ee, oe OR ee 37 grisceum, biological notes2s 2.2. fae oe oval k cee cee ee ee 45 hostiot Catolaceus wicertus®-.3 eee. eee eee 37, 43 in Phaseolus perennisi: = *-2 22-9 25-4-5 0 eee eee eee 37 segnipes, host of Hurytoma tylodermatis=.-<2=- 2 - =. = eee ee eee ' 42 Asecodes albitarsis, parasite of Magdalis xnescens..........--------------------- 43 Aspergillus sp., fungous enemy of boll weevil (Anthonomus grandis) ...-.--- 11, 28, 41 Anletes tenurpes, biological motes... 22 2-2. oes be ee ee eee 47 breeding period: .2-.7-2 2225). 0 seen ee 49 host of Catolaccus incertus. 222. 2. eee res ee ee 43 Balaninus, ‘host of Urosigalphus armatus.o22.-4: = 2-65 se ee ee 38 nasicus, host of Myitophasia wnea.-. 9-22-22 ee 9 eee 40, 42 INDEX. 55 momanmus nasicus (7), host of Trichacis rufipes.......-.....--...---.--n ee eeeee 42 ia spp., hosts of oon i a SAR RS ris IE cia oc nhs ws wei © ou ore Ad Baris sp., host of Bracon sp... - a OSS i 2S ee 44 Birds, factor in control of boll oe PG rege oe SG aieiw ve es Riel, AE Rian? He 3 =) Blackberry, food plant of Anthonomus signatus...............------.eeeeeeee 45 Bolls, fallen, percentage of parasitism of boll weevil.................... 14, 15, 16, 21 hanging, percentage of parasitism of boll weevil................. 14, 15, 16, 21 percentage of parasitism of boll weevil in 1905.................22....... 13 Boll weevil (see also Anthonomus grandis). SOLO) TE SE 2 ee er 3 MamnEMIOaD AMALIE PAPARUUISM De Soon a ool Siva ook wn wh wie ee ie ie ole Be 21 mermnREIEN TE WHOLEL OW ACER Gn se occ. acne nee beeen eee cen ecco ees 5, 22 aI ESN ENS ee fi cd ve cen Solan cde me mt ww clase o's 3 (2 2 SERGE EU IN hc Se oa a 28 parasites. (See Parasites of boll weevil.) predaceous enemies, list..........-..-..------ Se Ao 2 ieee eee 28 Oe UDO SIER 210 BIS eas ne en er 27-28 Pia AuOnUTOrMS, PArASlGISM -... 2. ..-2---- 5220-2. 2ceneee- 22 SEIMEI ORUES | PALASUGISM S05. oe ae cee se ee See = 22 cose UE QU OD DR Ter aT) Wight SR: a rc 19-20 Tne errs. DIOlOPICAl NOLES. .....+-...-+----.------------+----0% 47 host of Microdontomerus anthonomi.............------ 32, 42 OOM MURITUAUS TM UOTOLNOSUS )o.5.— 2 osu en cscek oa me eae 32 RED RAO STO TANGO TER De tr 6 oo cin! apa boop nse pela eee eee bee 44 irdcon analciars, parasite of Tyloderma fragarix........----.-..-.-..--------- 44 anthonomi, parasite of Anthonomus signatus........---.-------------- 44 nee ree-meaERTT in iS": TIUCUITLOT sa Sols te ne oo wade ee ein ee ee eee oe 11, 29, 38 Deets 1 eget Pe eee ke te 29 Pam OM POU Ce vile tus: 5.55. F284) 2 5s a eee en ee eee eee 11, 28 EE RIE AT COMETS be Arias 2 ot On 506 SA 8 oo ones dee ee nese 49 mellitor, accidental host of Cerambycobius cyaniceps, Eurytoma tyloderma-* ¢ tis, and Microdontomerus anthonomi.......----- 28, 33-34, 34-35, 37 artificial propagation as parasite of boll weevil...........-..---- 22 OLS T e2ueti oS 2 ee ae 9 ee a 38-40 2 VRUEID, (OPPAOTICUCE M0100, 2 lg ee ra a ee 11, 29 TAMCROSIIGULG ASV MON VAM oF. 22. ce le See se eee 29 center of activity as boll weevil parasite...........-..--------- 9 SEEN Th OG UU 0 OEE OC Re a 49 geographical and seasonal distribution...................-.---. 31-82 WOES) AUSTE & Soet ee) STS a 44 EIREIILETTC ee eee et Se ae oo So ce auw, ds oe een seen eeeee Maus 29, 30 parasite of Anthonomus albopilosus...-..-. ee eee 46 CUQ CTU Sh IL US en ae ee 46 BLUR nes Rane aN 32s Se che ee 45 SQUAMOSILSS ns aetna een a eee 46 boll weevil. . aye Leh Sn ee er bud, flower, pod, and seed + Ww eens 5 a, Se ek epee eae 48 OE SIONUSASCADUI RS atts 2-82 etd «kei. mio oe ae ee 45 BEE RGETE TIT IL Sie cps a Sic Peo nn Se nl iain ee ow gs 25, 26 rotation of hosts. - Se re eR ae Le eee ee ete, 48 pissodis, parasite of Penis obi. ed oe Aas tS Cd ads Uinta eee eee 44 rhyssemati, parasite of Rhyssematus lineaticollis..............--..------- 44 smicronygis, parasite of Smicronyx tychocvaes........: EE ER See Eee te 44 56 PARASITES OF THE COTTON BOLL WEEVIL. Page. Bracon‘sp., parasite of Barie ap2s =<. silos eo he ee oe ee eee ad Brachytarsus limbatus= 25/22 oe a eee eee 44 TOMCUS PIs 295 et oes See ee eee 44 ranthostigma—= Bo mellitor == - 22522 eee eee LCE eaves, wees 29, 38 OCCUITENCE 2... toi F Se ake. Meee eee en hee ee 29 Bratonid parasite of boll weevils. te se ee eee ee ee Lee 29, 40 Breeding records of parasites of boll weevil, 1906.........-.-..----.---------- 13-22 work on parasites of boll weevil 5.7, 2222 Le eee es eee ee 11, 27-41 Bruchide, probably a connecting link between Anthribide and Chrysomelide. . 47 Bruchobius laticollis, parasite of Bruchus pisorum..........------------------- 42 Bruchophagus herrere, Occurrences). 1653222822. ee aoe ee ee eee 29 parasite of boll weevil (Anthonomus grandis) .. . - - 14, 27, 36; 42 new, bibliographic reference: 222s Mia222 Soe: ae ee ee - Ol Bruchus ervguus, bioldpical notess< =: 427-28 esse eae Pee ee 48 host of Catolaccus inceriilss2ee = sees 38a > ee 37, 43 Cerambycobiusicyaniceps 22 oe ee 36, 42 pisorum, host of Bruchobius laticollis......-.-..---- oot! TAC eee 42 prosopts, host of Urosigalphus Driicht=2- o-oo ee ee 38, 44 in Prosopisiglandulosa sso see 2 eee te ae nat seme See oe 38 Callirrhoe involucrata, food plant of Anthonomus fulwus............---.------- 39, 45 Calyptus tabvator, parasite of Anthonomus signatus. 222-022. 2.22282 eee 43 Cathartus: cassix,.enemy of bolltweewil = 3-4 2 a2 te eee eee 28-41 OCCUTPENCE® 2 8. ee er RR any . 5. 22 oe gee Ae re 43 . in.’ Mentzelig nudaz 23 3.2 2 a ee ee ee ee 34 Parasites; factor in control of boll weevil... 4 6 2 eee eee 3-5 known. to.attack Rhynchophora:ic>.2e4:) ca een 8 ee 41-44 of boll: weevil; artificial propagation.) 5=— a ee ee 4, 22 bibliography: 4552222 0-222 -2 os ee ee 51-52 biological motes... 242-0.) -- eee eee ee eee 32-41 biologies of weevils contributing them.............-. 44-48 breeding records.of 19065. 20.227 3S ee ee ee 13-22 breeding work:225-57%. 2st Pe el ee 11, 27-41 CONCLUSIONS ....0.5. Je sss Fees e ep ae ee ene 50 from workiof (9062.23.25 2 toe 21-22 elimination of natural hosts [other weevils]. ....-.---- 4-5 examination. WOrk:..< 25-5 24s2s022 oS ne ee 11-22 field work. 2-23. ecivebo See ee 24-27 geographical and seasonal distribution..............-- 31-32 hibernation in, bolls: 5-2: 320 fens eee eee 12 historyas. 555. Soe 8 5 eee ee 10-11 IntensIVE Centersie3\..2. 233 Wee ae a 9 occurrence of species. 2245, 34 te oe a eee eee 28-31 percentage in bolls versus squares in 1905........-.-.-- 13 propagation work.0 2. o5) ae Dae oe ee 11, 22-27 Prospects <2. 2. f etd ec Nat sae ae anya a 50 records prior ito,L906..2. 22522) Boe: Se ee 12-13 release. ex periments. 23.5.4. Sone e ee ee 24-27 rotation: of hosts? 335. See eee 48-49 schemes for increasing their work..........-----.---- 48 source work 2.422% 370 5e 4" ee eee a 11, 41-50 transfer or artificial propagation, apparatus and diffi- CUltIES 125 Stat Bea a lo Se ee 22-24 work.ot 1906) conelusionss222 4: fee o se ee 11, 50 Parasitism and status’of. boll weeval: 2225.25 ee eee 19-20 of -boll weevil and-chronology :2.3. 62% 23 So ee eee 21 by. months, 1906... ..25te.ceee eo ete eee ee 14 field ‘conditions: =. +: Sa. 36032. 22 ees eee 17-18 geographical considerations... 3)-24552-2.=--- eee 18-19 in Tallen ibollsss 2. eee es ES eh Bree Ts 14, 15, 16, 21 fOYMS 2s. 45 22 SE sons Gace 22 in, shade) versus sun: 3." 5s 2 ece eee 17, 18,22 SQUares cece meee ee ane = eee 14, 15, 16, 21 forms in prairie versus woodland.........-..--- 17, 18, 22 hanging: bollsi_-e= 362. see ee ee 14, 15, 16, 21 TOUTING 526.52 eyx ds ag pelea eecvere ee oe 22 SQUATCS So. 352 oo See nt ene 14, 15, 16, 21 percentage by years, prior to 1906..............-.---- 11 plant conditions,most, favorable.- 4-2-2 soo ee 15-17 Peach curculio. (See Conotrachelus nenuphar.) INDEX. 61 Page. - Pediculoides ventricosus, introduction into Texas an unsuccessful attempt... ... 40-41 Si SE Si ey A ge 30 parasite of Anthonomus eugenii...........-.-....22004- 42-46 boll weevil (Anthonomus grandis). 10-11, 28, 40, 42 » Peppers, food plants of Anthonomus eugentt......-......------.- 22 eee 37, 39, 46 Phanerotoma tibialis, parasite of Anthonomus nigrinus................-..--2-- 44 _aseorme perennis; food plant of Apion griseum...:....-...-.....----20ee eee ee 37-45 Phleosinus graniger, host of Spathius canadensis.............------------------ 44 Eres CONMPLANA— ANCYLIS COMPLANG.... 2... 2222 ee ee ee eek 38 Phytonomus punctatus, host of Empusa (Entomophthora) sphxrosperma and GTS TOI IC tte Ag a ip Bi aay a 4] pmeeeserrout, Nosh of Bracon pissodis............2........002.40-- CESS af 44 Pityophthorus consimilis, host of Cerocephala pityophthori...........-...-...---- 43 eMOMINOl MAYSSalUs PULYODNUNOTD.- 2.02. ck eS 44 Plant conditions most favorable for parasitism of boll weevil.........-......-. 15-17 Plum curculio. (See Conotrachelus nenuphar.) Podapion gallicola, host of Sigalphus copturi................22--2022-220--202- 43 Polygonum pennsylvanicum, food plant of Lixus muscu mits Ber (Hee aye 25, 34, 36, 45 Porizon conotracheli, parasite of Conotrachelus nenuphar..........-.--.--------- 43 Potato-bud weevil. (See Anthonomus nigrinus.) stalk weevil (see also Trichobaris trinotata). EMG Ta pincEeIenenee- too. 2. seo ee eke 51 Senne seri anintcrmnn DOM WeeVILs s. 5222222520202 l 2 lee. eee eee 17, 18, 22 Reersiion. iacvorim conirolof oll weevil...2.........205..0. 0050022 ee eee 3 Propagation of boll-weevil parasites artificially, apparatus used, and difficulties. 22-24 wars oneparasites of boll weevil::-)2J2:. 022.02 2..22.0.-.-.26. 11, 22-27 Prosopis glandulosa, food plant of Bruchus prosopis.......-.-.--.-------------- 38 menpoery, 1000 plant ot Anthonomus signatus.:......---2-----2-2 +. 0 ee eee 45 Red-bud, food plant of Anthonomus signatus........----- Rater Sah Ss 45 Rhyssalus pityophthort, parasite of Pityophthorus sp......---------------+--+--- 44 Rhyssematus lineaticollis, host of Bracon rhyssemati.........-.-...------------- 44 0 EGPCS TE G3 ¢ 232571 5 2s 1S A RS Ae 41-44 Pee wil. iood pant of Anthononus signatus.......02--..5-2-22-------- +26 45 Sealyiid, host of Cerocephala scolytivora....:......-....-..1--.2 2. eee eee 43 Seen te COploM squATeS ©: 32202 2402.22. tee 7h Beate eae OE a 10 eee tre OIOI! WWEOVI: 5005222 s fc. Fk see eee ee ee 17218822 _ Sideranthus rubiginosus, food plant of Brachytarsus alternatus.......-.....-.---- 32, 47 Desmions scapalis: 1). 222-22 ae Be 39, 45 Sigalphus canadensis, parasite of Anthonomus scutellatus.......-..------------ 43 CEE Be SAS LISE LOST SS TODS SRS SS aL 43 curculionis, biological notes..........----- SPR Gys Raga IN Sih Phy os esi eta 38 EES GLE SSG tg Ss Ar Af DSP BORLA OS 4 Sie See ee ae See ere ere 29 parasite of boll weevil (Anthonomus grandis) ......--- 11, 28, 46 bud, fruit, pod, and stem weevils.........-.. 48 COnomrachelus Nenu phate... 238) .42- 052 5228. 46 Dri Chooaiis ATIN CIOs sse'es esas) 22 ie ok 47 sp., parasite of Chalcodermus xneus...-. - - Sep eae ey he 44 zygobaridis, parasite of Zygobaris xanthoryli............---.--+------- 44 Smicronyx tychoides, host of Bracon smicronygis.......-.----------------------- 44 Solanum carolinense, food plant of Anthonomus nigrinus.........-.----------- 46 eleagnifolium, food plant of Anthonomus xneolus.......-.-.-.------- 46 rostratum, food plant of Anthonomus x#neolus.......-.-.-----------+-+- 46 62 PARASITES OF THE COTTON BOLL WEEVIL. Page. Solanum rostratum, food plant of Trichobaris terana.............-..---- 25, 36, 38-47 occurrence with reference to that of Cerambycobius....... 49 spp., occurrence with reference to that of Cerambycobius...........- 49 torreyt, food plant of Anthonomus xneolus......-....---------------- 46 Solenopsts geminaja, enemy of boll weevil... --< 2-2 -2e ene se sagen ee arpie en eee 3, 28 Source work on parasites of boll weevil... --<<25142: = 305. eeeekes armpits 11, 41-50 Saotvius canadensis, hosts, Vist. . 0 oe 02 es cee in aa ee 44 Sphenophorus parvulus, host of Myiophasia xnea.......-...-.-.--------------- 40, 42 robustus:. host of Miytophasia robusta... 2...) oe ea oe 42 Sporotrichum globuliferum, fungous enemy of Epicerus imbricatus........-.-.- 41 Squares, fallen, percentage of parasitism of boll weevil........-.-...-.-- 14, 15, 16, 21 hanging, percentage of parasitism of boll weevil .........-.....- 14, 15, 16, 21 percentage of parasitism of boll weevil in 1905.........22-2.....-.--- 13 Strawberry, food plant of Anthonomus signatus.........---------------------- 45 leaf-roller. (See Ancytis comptana.) weevil (see also Anthonomus signatus). bibliographic reference 420.5 9227 sae se eee et oe 51 Sunlight and dryness, favorable to parasitism of boll weevil .............-.----- 22 Simeparasitism of boll weevil 2.25. 240 i ee ee eee ee 17, 18, 22 Tachinids, conditions favorable to parasitism of boll weevil............--..-- 22 herastichus sp-, parasite of Orthoris, crotch. #.22 5.2. 8 ee ee 43 ROTLICUS PINT, NOSt OL -Bracon Spas. - = 2) S28 ase ae eee ee ees 44 Sp-;, host. of Spathiwis canadensis = 2a e 2 5 44 Trichacis rufipes, parasite of Balaninus nasicus (?)....------ PP eo Ay ea, 42 Praenovars texand, biological: noes... - = 2484s ae ee ee eee eee 47 breeding, Period jc. ss tee see ee ee 49 host of Cerambycobius cyaniceps 322 S22 2 Ne ee 25, 36, 42 In. Solanum TOSI Abu 2 hee ee ee eee 25, 36 trinotaia, host of Sigalphus curcilionits-2 7) a eee 38, 44, 47 in Solan TOStnQlUMn 22. = oe ee 38 Tyloderma foveolatum, biological notes: 222... 3... -c. 222 ones a eee 47 breedine period 2. 2 st. 3- 2 2 se so ee a fs 49 host of Cerambycobius cyaniceps .........-------------- 36, 42 HArytoma TylOderM Gis. =... oe oh ka ee 34, 42 Neocatolaccus tyloderms ...22-2 22 eee 43 in: Onagnabiennis 2 2e2 0 a eine ee ee ee 34, 36 Jragore; host of Bracon analogs 2.2.5 2 = a eee eee 44 Tyroglyphus breviceps, parasite of Anthonomus eugenii...-...------- tse a Soe 42 boll weevil (Anthonomus grandis)... 11, 28, 30, 41, 42 Urostgalphus anthonomi, biological notes:.. 2... 2.22.22 -2s2s-26 ces ae cee 38 OCCUITENCE. 3245 252 eee ee eee ee eee 29 parasite of boll weevil (Anthonomus grandis)... - - - 11, 28,44 Ormaus,. parasite OL Balaninuss>-.2i=. eee ee 38, 44 Conotrachelus spp-- 3-2 saee2 ao eee dt brucht, parasite of Bruchus prosopis:- =.= 2see >] - oes eee cee 38, 44 (robustus). (See Urosigalphus anthonomi.) . Schwarz, OCCUITENCE. co.cc o.. Soce eee ee eee eee 29 parasite of boll weevil (Anthonomus grandis)......-.-- 28, 38, 44 Vepro belfraget, parasite of Jizus scrobicollis <3 0 sec. tee ee dd Weevils contributing parasites of boll weevil, biologies..............-...------- 4448 Winter temperatures, factor in control of boll weevil.............-.....----.--- 3 wvoodland, parasitiam of boll weevil.....%-.2 220 oS eee ee ee L716 22 |