QUEENSLAND. _ BUREAU OF SUGAR EXPERIMENT STATIONS. |! DIVISION OF ENTOMOLOGY. BULLETIN No. 16. 3 Australian Sugar-cane Beetles and : their Allies. BY J. F. ILLINGWORTH and ALAN P. DODD. | BRISBANE: By Authority: Anthony James Cumming, Government Printer. ~- 14-6-21—2,000 ; 4 SEE aS eae Raters a ss a ES sta 7 ne Ah % om hoe en ee QUEENSLAND. BUREAU OF SUGAR EXPERIMENT STATIONS. ee i Sa GHEY. BULLETIN No. 16. Australian Sugar-cane Beetles and their Allies. J. FE: TEEINGWORTH and ALAN P. DODD: Lg) ade BRISBANE: By Authority: Anthony James Cumming, Government Printer. Bureau of Sugar Experiment Stations, 3risbane, Ist September, 1921. The Under Secretary, Department of Agriculture, Brisbane. Sir,—I have the honour to submit for publication, as Bulletin No. 16 of the Division of Entomology, ‘‘ Australian Sugar-cane Beetles and their Allies,’’ by Messrs. J. F. Illingworth and Alan P. Dodd. I have, &e., H. T. EASTERBY, General Superintendent. Approved: E. G. E. Scriven, Under Secretary. FOREWORD. A Tue title of this paper indicates a tremendous subject, a fact all the more patent when one realises that the grubs of fully 50 species of Searabeids have been taken in the canefields of Australia. Fortunately, the great majority of these are held in check by natural controls, only a few species becoming so abundant as to menace the sugar industry. The writer undertook an investigation of these pests, in June 1917, being located at Meringa in the Cairns district, North Queensland. Already, during the preceding six years, considerable life-history work had been carried on by the Division of Entomology of the Bureau of Sugar Experiment Stations, the results of which had been recorded in the first six bulletins. Hence with this substantial groundwork it was possible to begin field experimentation at once. Primarily, our attention has been given to the most serious of all cane-pests, Lepidoderma albohirtum, a species extending right up and down the coast of Queensland. Therefore, except where; otherwise mentioned, the following notes and descriptions refer only to this species. It gives me pleasure to express my appreciation of the tremendous amount of tedious, painstaking life-history work which was done before I took up the investigation, by A. A. Girault, A. P. Dodd, and E. Jarvis. Furthermore, I wish to render an especial acknowledgment to Ma. Dodd, who has assisted me loyally in every possible way, often working early and late in order to accomplish results. He has also collaborated in this paper, writing the sections under his name. Then, too, all of the drawings, except where otherwise stated, have been made by Mr. Jarvis. And, finally, I must note the cordial assistance of both the millers and growers, who have spared no efforts to facilitate the investigation. PLATE I.—STAGES IN THE DEVELOPMENT OF LEPIDODERMA ALBOHIRTUM WATERHOUSE; ALL NATURAL SIZE AND COLOUR. Fig. 1. The newly emerged beetle. Fig. 2. The egg-chamber in the soil, with eggs; just laid. Fig. 3. The full-grown grub. Fig. 4. The pupa. late Del, E.Jarvis Fy . h & - ’ 7 ter i (a 7% m OD Tie a if 1 Tew | - i F A 1 : | I, i= i = { Pel : a ‘a | a ~ ‘ 4 ' wi \ j i 1 e ‘ nel I iT j oa i i Oe ip ~ I 7 « ' i : Dy. ’ 1 * : os 7 - a : i A %. : oe t9 i fi n rs 1 ms 5 \ — . 7 1 n ‘ - ‘ . ‘ if i — an ” ' « . n n ’ f f j ; ‘ j 7 ; i é Australian Sugar-cane Beetles and their Alhies. eee eter By J. F. InLIngwortu. THE GREYBACK CANE BEETLE, LEPIDODERMA ALBOHIRTUM WATERHOUSE. THE NAME. THE type locality of this species is Bowen, North Queensland, the species having been named by C. O. Waterhouse in 1875." Neverthe- less, subsequently there appears to have been considerable confusion, especially in Queensland, as to the correct terminology for this insect. Reviewing the literature on the subject, I found that R. E. Turner (6),+ speaking at the Agricultural Conference held at Mackay on 23rd and 24th September, 1892, used the name Lepidoderma albo-hirta. And, a year later, Sydney Olliff (8) mentioned Lepidoderma albo-hirtum among the beetles infesting sugar-cane in New South Wales. The next reference that I was able to locate was the excellent bulletin by H. Tryon (19) on the Grub Pest, published in 1895. He referred to this species as Lepidiota albohirta, and, further along on the same page, he used the name L. squamulata for it, as he likewise did on the title-page. In his subsequent writings, however, I found that Mr. Tryon used the name L. albohirta; and later changed the form of the specific name, in his annual reports for 1907, 1908, 1909, to albo-hirtum. In Australian Insects, 1907, on page 157, W. W. Froggatt used the correct terminology, as did also Rey. T. Blackburn, in his paper published in the Transactions of the Royal Society of South Australia, 1912, p. 52-3. On 30th January, 1912, A. A. Girault wrote to the United States National Museum for advice on the name of this species, and Dr. E. A. Schwarz, the eminent custodian of Coleoptera, replied, 29th March, 1912, as follows :— ‘* Lepidiota albohirta is no doubt the beetle described as Lepidoderma albohirtum by Waterhouse in Tr. Ent. Soc. Lond. 1875, p. 202. The genus Lepidoderma being closely allied to Lepidiota is probably not recognised as valid by the present Australian Coleopterists, but I have no means of speaking definitely about the subject, because the lhterature on Australian Coleoptera is at present not at hand. Moreover we do not have the above species in the collection of the U. S. Nat. Museum and should be glad to get specimens. The type locality is given by Waterhouse as Port Bowen and no other locality is mentioned by him. The type or type specimens are in the British Museum. I regret very much that I cannot give further information on this beetle.’’ Subsequently, nevertheless, Girault continued to designate the species as Lepidita albohirta; furthermore, it was so determined for * Trans. Ent. Soe. Lond. 1875, pp. 201-2. + The numbers in parentheses refer to the bibliography. 6 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. him by Mr. A. M. Lea, Entomologist of the South Australian Museum, l4th May, 1914, except that Mr. Lea used the original ending, wm, for the species. Hence, in the later writings from this station the misnomer continued to appear. On 21st December, 1920, I wrote to the South Australian Museum for Mr. Lea’s further assistance in clearing the matter up. In reply, 7th January, 1921, Mr. Lea supplied a copy of the original description, leaving no doubt in my mind that our common ereyback beetle is Lepidoderma albohirtum Waterhouse. HISTORY OF THE, PEST, A review of the history of almost any pest is both interesting and profitable; furthermore, it lends perspective. Unfortunately, isolated as we are, it has been difficult to locate many of the earliest records of grubs damaging sugar-cane. Tryon (19), however, in his excellent bulletin on the ‘‘Grub Pest of Sugar-Cane’’ throws considerable hght on the subject, especially for the northern districts of Queensland. His earliest records are from the Mackay district, as follows :— ‘During 1872-4, at Branscombe Plantation, the cane growing just outside the serub land, and between it and the forest land, died off, and in ploughing out the stools the roots were found to have been gnawn through, and coekchafer grubs were found under the stools—from five to twenty in each case (W. E. Davidson). They also occurred then on the Pioneer Plantation, of which Mr. Spiller was the proprietor. In 1874-5 some acres of cane at Miclere Plantation succumbed in a manner similar to that which occurs when grubs are present (W. T. Paget), and at Richmond Plantation, a field of seventy-five acres in extent was wholly injured by them. In 1885 they were prevalent on the Cedars Plantation, for at that time some forty or fifty acres of sugar-cane had, in consequence of their ravages, to be ploughed out, and the land oce upied by it had to be replanted three or four times before they were ultimately oot rid of. They were also at that time met with on the alluvial forest lands at Farleigh. That it was still a generally recognised sugar-cane pest in the Mackay district in 1885 appears from the fact that H. Ling Roth, in his article ‘On the Animal Parasites of the Sugar-cane,’ referred to it as being ‘one of the most destructive creatures’ with which planters had to deal, and as effecting the destruction of ‘whole fields of cane.’ At Dumbleton Plantation grubs were very prevalent prior to 1887 (H. H. Lloyd), and at Inverness Plantation it had already proved destructive, especially in dry seasons (J. McBryde). In 1888 we learn of its occurrence at Cortweed, where it destroyed at that time a quarter of a plantation of 150 acres (Z. W. Christensen) ; and again at Homebush, during the same year, 400 acres of cane had to be ploughed out by reason of its presence (R. G. Smith), and at Te Kowai at the same time the crop was also very much affected, the roots of the sug sar-cane covering a good many acres being eaten by it (J. E. Davidson).”’ That the grubs continued their destructive work in the Mackay district during the next two decades is evidenced by the numerous com- ments on that subject appearing in the Sugar Journals as well as other publications. Of special interest are the remarks of W. T. Paget (17, 18), that the grubs had made their presence felt at Mackay in 1893, and in 1894 they were very serious. Again (29), in 1899, he remarked at ithe Agricultural Conference, at Mackay, even after destroying four tons of beetles on their estate in 1894, the cane was ruined the next GREYBACK CANE BEETLE, LEPIDODERMA ALBOHIRTUM. if vear just the same. Many of the principal feeding-trees had been removed subsequently, but Mr. Paget did not consider that this was responsible for the disappearance of the beetles in his section. He considered the district free from the grub-pest in June, 1899. At the same meeting, E. Swayne (31) said that it had been twenty-five years since the grubs first appeared in Mackay, and in 1891-2 their numbers were so great that they threatened the stoppage of the industry. During 1895 the Agric ultural Department voted £1,500 to assist in their destruc- tion. From 1896 to 1899, 504 tons of beetles were collected at an expense of £2,649 19s. 7d. Even as heed as 1909 the Mackay Mercury (44) stated that receivers had destroyed 22 tons of grubs in that district; and in 1911 (47) they again collected 22 tons. They give the interesting figures that a ton of beetles is equal to 560,000, since Shere are about 250 to the pound. Moreover, the grubs had become troublesome in a number of other sugar-growing districts, both north and south of Mackay. In January, 1891, Albert Koebele (1) found several species of grubs damaging the cane-roots in the Clarence and Tweed River districts of New South Wales. He says :— ‘Of these a species of Anoplognathus, commonly ealled ‘Christmas Beetle,’ was most numerous, and is often ploughed up both in the larv and imago state. Two other species of large Scarabeid larve were found behind the plough, as well as a species of Heteronyz, together with larve and pupw, no doubt of the same species.’’ As a control measure Koebele recommended shaking the beetles from the trees early in the morning, when they could easily be picked up and destroyed. He also says :— ““They are readily attracted by hghts, and may be collected with traps consisting of a bright hg¢ht placed over a tin or other vessel about a foot deep by two feet wide, with perpendicular sides and with about two inches of water in the bottom. Many such simple traps could be placed over the fields In December and January, when the beetles are on the wing. Dark nights are best for attracting insects. Without doubt the presence of toads, if these were introduced, would have a remarkable effect in diminishing the numbers of these as well as many other injurious insects. ”’ In June, 1892, Professor E. M. Shelton (4), of the Agricultural Department, at the suggestion of some of the afflicted growers, wrote Dr. C. V. Riley, Chief of the Division of Entomology, W ashinet ton: DsGe as follows :— ‘It has been in my mind for some time to write to you concerning an insect which interests Queensland planters in a very practical way and about which I hope to interest you. Our plantations, particularly those devoted to the growth of sugar-cane, are just now suffering from the ravages of a dreadful scourge in the shape of a grub, very like the larva of the Lachnosterna fusca of your country. This erub literally swarms in nearly all the canefields the whole leneth of the Queensl and coast. I can give you many facts to show the extraordinary voracity of this pest and the extent of its rav ages. One planter assured me that upon an estate of 1,000 acres he has 400 acres of cane. Another figures his loss during the past at between £4.000 and £5,000 sterling. Cases of this kind might be multiplied almost. indefinitely. ‘“‘T may say that the insect itself is known as Lepidiota squamulata. So far planters are powerless in its presence. The only attempt at 8 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. circumventing it is made by hand-picking. In the South Sea Islands a boy* follows every plow with a four-quart tin pail, and very frequently he is able to fill this pail in going across a small field. The travelling inspector of the Colonial Sugar Refinmg Company tells me that upon one of their plantations they have during the past season picked of these grubs no less than 700 pounds weight from a single acre. You do things in a large way in America, but can vou beat this? ‘T have recommended the planters to try kainit, which I see referred to in Inseet Life as having been useful in the case of cutworms and other underground larvae, but so far the kainit has not the shghtest influence in checking the ravages of this grub. Can you suggest anything in the way of a remedy? If you can only give us a hint in this direction that is at all workable I can promise you that your reputation in Australia, great as it now is, would be made so far as we could make it. I notice in one of the American papers a statement to the effect that a French company is sending out hermetically sealed vials containing a fungus which is said to be most destructive to larve like the one under considera- tion. Do you know anything about it?’’ In reply Dr. Riley wrote : — ‘“The imsect which you report as so seriously affecting sugar-cane plantations on the Queensland coast is, from the very nature of the case, as you will readily see, a most difficult one to counteract. The occurrence of this insect and its work have never been brought to my attention and its habits in the imago state are altogether unknown to me, though | doubt not similar to various American Lachnosternas. In this country, particularly here in Washington, we have very successfully treated lawns infested with white grub by soaking the ground with kerosene emulsion, as deseribed in the first volume of Insect Life on page 48. and I believe that this will perhaps prove to be the only practical remedy against your insect. The emulsion of kerosene could be distributed by means of some of the injecting devices manufactured in France for use in disinfecting vineyards of the Phylloxera with bisulphide of carbon, and this latter substance, too, would be an effective remedy against the grub were it not for the expense of applving it en so large a scale. The expense of the application would also be a great obstacle to the use of kerosene emulsion, though this last would be much cheaper than the bisulphide. At this distance and in entire ignorance of the habits of the adult insect, I can give you no further advice as to the best remedies. It is possible that the food-habits of the adult insect will furnish a more easy and practical, not to say cheaper, method of controlling it. This would be the case if the beetle is known to feed on any plant which could be sprayed with Paris green or London purple. I should be glad to get specimens of the insect in all stages, and also, if you can furnish it, a full account of its habits in other than the larva state. ‘With regard to the White Grub fungus which the French firms are advertising, [| have no confidence whatever in it. I have experimented with it and believe that the results have been generally overstated and that the fungus is being pushed merely as a speculation.”’ During the Agricultural Conference held at Mackay on the 23rd g S , and 24th September, 1892, Mr. R. E. Turner (6) delivered a most instructive address on the subject of ‘* Insect Pests,’’ dealing primarily * Obviously there is a mistake here, and what is probably meant is that ‘‘a South Sea Island boy follows the plow’’ in Queensland. GREYBACK CANE BEETLE, LEPIDODERMA ALBOHIRTUM. 9 with the cane-grub. He mentions two species as being most destructive, Lepidoderma albohirtum and Anoplognathus lineatus, which is now known as A. boisduvali. Further, he remarks :— ‘As these insects are native and only attack the cane incidentally, their natural food being the roots of grasses, it is Impossible to exter- minate them, for even if we succeeded in clearing the canefields of them at one time beetles would soon find their way from the uncleared land and deposit more eggs. It is, however, very unlikely that any considerable increase will take place in their numbers if we protect their natural enemies, insectivorous birds. At present, I am sorry to say, we are doing just the opposite. Some laws indeed do exist on the subject, but such laws are useless unless backed up by pubhe opinion. Very few even of those directly interested in agriculture think of discouraging the slaughter of birds and the destruction of eggs by their own children, henee it is seldom that birds are seen in any number in the neighbourhood of a homestead. . . . Many birds prey on the insects, both in their erub and perfect stages; some are able to detect the presence of a grub underground. I believe that the bandicoots, although usually as we all know not far from vegetarians, have no objection to the grubs as a variation in their diet. | will not go so far as to recommend the protec- tion of bandicoots. Frogs and lizards destroy a great number of beetles themselves; the former are not much interfered with, but a good many of the larger lizards are destroyed, owing to the peculiar and mistaken but very prevalent idea that they are venomous.’’ 15th November, 1892, a correspondent (3) of the Sugar Journal wrote that the grub-pest was unusually severe during the preceding two seasons on the Herbert and Johnstone Rivers, and stated that most of the injury was undoubtedly due to the larve of Lepidoderma albohirtum. In a report on a visit to the Clarence River district, N.S.W., March 1893, Sydney Olliff (8) recorded several species of beetle larve found at the roots of sugar-cane. Among these he recognised Anoplognathus concolor Burm., Lepidoderma albohirtum Waterh., Lepidiota squamulata Waterh., and a Heteronyx species, but in no case did he find them numerous or destructive. A report (10) published in the Sugar Journal, July, 1894, said that the grubs had done most serious damage for years on the Johnstone River; and further on in this same report is Mr. Swallow’s most interesting account of their status in the Cairns district. (It must be noted that this report was originally published in 1893 for private circulation among the officers of the Colonial Sugar Refining Company. ) ‘We first noticed the grub-pest seriously between three and four vears ago (i.e. 1889), and it was all over the estate and right up to the Pyramid Plantation; in fact, around the place generally things looked very serious for us, so we came to the conclusion that something must be done at once to check the pest. That year one-third of the estate was ploughed out after the cane had been taken off; 40 acres of cane gave but 10 tons sugar, through the grubs being so bad. All wood lying on the ground was either sent to the mill as firewood or burnt; all trash, and in fact anything that would burn, was burnt. ‘“We, at the same time, started a travelling fowl-house on wheels, holding about 100 fowls. These fowls were taken to the field and turned out loose behind the ploughs. In the early morning they answered well, but as their appetites became satisfied they would come back to the house and rest, going out again as they became hungry. One kanaka boy had 10 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. charge of them, and had to see that they were shut up safely at night- time. It is wonderful the amount of good that these fowls did, as in many cases just by a little scratching they often turned up grubs which had been missed by the boys following the ploughs (boys with tins were behind each plough, harrow, &c.) ; and, again, when the grubs were very small, there being more chance of them being missed by the boys. As regards the eggs, we have never discovered the eggs in the eround, but have noticed them in beetles which have been killed. Besides fowls we have at times a large number of black magpies, though they do not seem to remain all the year round with us. While here Fives are, as a rule, very busy behind the ploughs and newly ploughed land, killing and eating the grubs. Ibises come here in large numbers, and they also attack and eat the grubs; we seldom see them on grass land, but as a rule on newly ploughed land. ‘We now have the greater part of our estate cleared of timber lying on the ground, and partly stumped. There are still a few stumps left in the ground, but these are being gradually burnt away when burning the trash off; the ploughs in consequence can go over the whole of the ground except a very small portion around the stumps. I am quite sure that it is having been able to get at all the old land, I may say, with the plough, turning it up, having boys and birds on the lookout for grubs and_ beetles, that we have been fortunate enough to get rid entirely of the grubs. At the present time (1893) there is not a piece of grub-eaten cane on the place that one can see. Besides looking out for the grubs great attention has been paid to the catching and trapping of the beetle. Casks were placed in and around fields, the cask was partly filled with water, a tallow lamp was made fast to a board nailed on and across the top of the cask, tar or molasses was smeared all over the outside of the cask. Thousands of beetles were caught in this manner, besides those turned up by the plough.’’ In 1895 the grubs continued so destructive that legislative measures were set on foot, in both the Mackay and Herbert River districts, in order that funds might be collected for the suppression of the pest. This matter was outlined by Mr. Paget (17), of Mackay, and later the growers, by a direct tax upon themselves which was finally augmented by a Government subsidy, expended many thousands of pounds in collecting the pest by hand, as has been indicated above. At the Agricultural Conference held in Mackay in June 1899, Wim. Beal (28) said that during the preceding ten or twelve years 30,000 acres of scrub had been felled in the Childers district, with a marked decrease in the pest. He considered that thorough cultivation was an important factor in the control of the pest. The Colonial Sugar Refining Company’s Annual Report for the season of 1907 (36) states that the Hambledon district lost fully 20,000 tons of cane from grubs during 1906-7, and that this loss had a net valuation of £20,000. Then, in their report for the season of 1908 (38), they estimate the loss due to grubs for their five Northern mills at 40,000 tons for the year. £2,800 was spent for the destruction of 31-73 tons of beetles, and Mulgrave spent an additional £1,000, And, again, in the report for 1909 (39), they estimate the loss for the Cairns district at £50,000. £1,500 was spent for collecting 14 tons of beetles and 2 tons of grubs. In 1911, G. H., Pritchard, Seeretary of the A.S.P.A. (49), while GREYBACK CANE BEETLE, LEPIDODERMA ALBOHIRTUM. 11 speaking on the subject of an entomologist for the sugar industry, remarked that during the season of 1910-11 over £3,000 was spent in the eradication of grubs in the Cairns district. They had destroyed 22 tons of beetles and 9 tons of grubs. It was estimated that there was an annual loss of 25,000 to 30,000 tons of cane in that one district. And, later, while on a deputation to the Minister for Agriculture in 1912, Mr. Pritchard (53) estimated that the annual losses from grubs on cane in Queensland were fully £100,000. NATURE OF THE INJURY. Grubs are most destructive on well-drained land; consequently, m Northern Queensland, erops on the red volcanic soils are usually the worst affected. These soils are very porous, often extending to a great depth, and underlaid with gravelly subsoils. As a matter of fact, they are so friable that they may be cultivated at almost any time, even during the rainy season when it would be disastrous to go on to the fields of heavier clay. Then, too, because of the loose nature of the red _ soils, especially in districts with heavy rainfalls, they are usually poor in both humus and lime, which, we shall see later, are of considerable importance for the growing of successful crops. As is well known, the grubs of the greyback beetle, Lepidoderma albohirtum—the prineipal cane-pest of Northern Queensland—are only destructive during a few months out of the year, from about February to May. During this time, however, they attack sugar-cane in any stage of its growth. Ordinarily the cane is well advanced at this season, but it makes little difference in what stage it is, for as soon as the weather turns dry the leaves begin to yellow and wither as if suffering from extreme drought. In badly affected areas, like the Greenhills estate, this is a most heartrending sight, especially when one considers all the effort that has gone into the crop; yet, year after year, hundreds of acres succumb in this way on the above estate, the leaves finally becoming as dry as if a fire had been through the fields. This drought-stricken appearance is due to the fact that the roots have all been eaten off and often the root- stocks, too, badly gnawed, so that one can easily pull the stools right out of the ground. In fact, I have sometimes seen the cutters jerk out the individual stalks, when harvesting grubby cane, because it was easier than cutting them off. Of course, under such conditions the ratoons are worthless, but in any case they are likely to be after such devastation by the grubs. Furthermore, in the case of mature cane the damage often occurs several months before the mills open up for crushing, and there is inevitably considerable loss through deterioration, for the lateral eyes on grubby cane grow out at the expense of the sugar content. Nevertheless, if there is no wind this cane does not usually fall down, and a partial return is secured from the crop. On the other hand, with a cyclone such as that of 10th March, 1918, or the one of 2nd February, 1920, all of the mature cane that has been badly injured by grubs is tipped right out of the ground, and many thousands of tons rot before it can be milled. With late-planted (i.e. September-October) cane, the procedure is somewhat different, for the crop usually grows well until about February, when it is ready to “‘lay by,’’ then suddenly, if there are many grubs present in the soil, it ceases to develop, and the leaves soon have 12 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. the same drought-stricken appearance described above. Under such conditions no cane develops, hence the final result is much the same: the crop 1s a total loss. With early planting (i.e. March-April) of grubby fields, unless they have been thoroughly worked for several months, the numerous full- grown grubs which are normally in the soil at that season at once attack the sets, which either do not grow at all, or if they do start the shoots are pale and attenuated, so that they often die out altogether, Examina- tion then shows that not only have the roots been mostly eaten off, but both the sets and the shoots also are often considerably gnawed into (Plate 2), especially at the cut ends of the former, the grubs themselves being often located in the cavities they have made. Under such condi- tions it is practically useless to replant the field until these grubs have hibernated. Moreover, the young plant cane is frequently injured by grubs at other seasons than that noted in the last paragraph, especially the late planted crop, in certain areas. This, however, is the work of grubs of other species, notably those requiring two years for the life-cycle. In forest areas about Gordonvale the large third-stage grubs of Le pidiota frenchi, whieh come up out of their dee p hibernating chambers about September, are capable of doing as severe damage, especially to young cane, as the grubs of the greybacks do at other seasons. In the scrub areas here this species is replaced by two others, L. caudata and L. froggatty, both of which may do as much damage. In the Cairns district the grubs of LZ. frenchi have proved a serious pest, since the third-stage grubs last for a full year in the soil, and are destructive to cane-roots for several months before the season for the greybacks begins. The general result of their work on the plant is the same; but the appearance of the field is usually quite different, for they work more in patches; there will be here and there an area a chain or so across Where the cane is almost dead, while the surrounding cane is thrifty and green. As I have indicated above, the change in appearance of grubby cane may be very sudden, espec ially following a considerable ainy period, if the weather turns dry; for then the few roots still remaining, which sufficed to supply the needs of the plant while evaporation was slight, suddenly prove quite inadequate, as indicated by a piping of the leaves even before they begin to yellow. This rolling of the leaves while there is still sufficient moisture in the soil is thus the earliest sign that the plants are suffering from root injury and lack sufficient moisture. Hence the general impression that the grubs are worse in dry weather is undoubtedly incorrect, for investigation demonstrates that most of the damage was done before, even during the rainy season, at which time the erubs work principally near the surface. This leads me to speak of the value of deep-rooting varieties of cane. On several occasions I have called attention to the grub resistance of D 1135, which is undoubtedly due both to its habit of deep rooting and its superior vigour. The roots are numerous and extend to a depth of 16 to 20 inches—far below the normal activities of the grub. Then, too, with this variety new roots are developed rapidly, hence the stool iaintains its grip on the soil even in the face of severe hardship, and does not uproot. It is most instructive to see stools of this variety green and upright, in the midst of a field of Badila that has entirely succumbed to the attack of grubs. GREYBACK CANE BEETLE, LEPIDODERMA ALBOHIRTUM., 15 That grubs are most destructive on well-drained soils does not mean that they do not exist in other soils, for quite the opposite is often the ease. Even on the river-flats, where the soils are normally well supphed with water, and the cane seldom shows any injury from grubs, I have found them to be very numerous, by digging; in one case as many as 16 per stool. Naturally we might conclude that this apparent immunity is solely due to the fact that the land has more abundant humus; yet I think a better explanation is that in the event of roots being eaten new ones are more quickly produced in this moist soil to replace them, hence the leaves show none of the withering effect. Most of these remarks have reference to plant cane, since on badly infested land it is seldom possible to secure ratoon crops. Nevertheless, in some instances the injury to the first crop is slight and the following ratoons are wiped right out. In fact, it is usually considered that the grubs are more destructive to ratoon cane than they are to the plant. My experience is that in the latter case cultivation can be carried close up to the plants, and is continued for a much longer period than with ratoons. Therefore, in most instances, if the plant crop is severely injured, there is little hope of securing a profitable ratoon crop the next season. Fortunately, if the grubs are with us, it does not signify that they will always be with us. In some districts they have disappeared as if by magic—possibly by disease or other natural cause; still there is no question that they leave the older areas as the timber is gradually cleared away and the country opened up; but they usually continue their depredations in the newer fields, which border the feeding-trees, in which case the ‘‘firing line’’ appears to be only moved back. I have neglected to mention that some of the beetles feed for a brief period upon the leaves of the sugar-cane, producing scars similar to those made by cutworms or grasshoppers (Plate 3). They have often been noticed taking their first meal on the cane before flying away to the feeding-trees, but whether this is a customary performance has not yet been demonstrated; in any event I have never observed any serious injury resulting from it. However, it has been recorded by W. T. Paget (18) that when the natural feeding-trees of the chafers were destroyed at Mackay they ate the cane-leaves; but the reference does not state whether the injury was extensive enough to be serious or not. Finally, as Tryon (19) has pointed out— ‘*Failure in the crop, for which the grub-pest has been held respon- sible, has been partly due to the co-operation of the gumming disease. It must not be inferred, however, that this has always been so, for such an inference would be quite contrary to what is actually the case; much less is it true that the grub-pest manifests a preference for ‘gummed cane,’ or, indeed, for such as is not in a condition of perfect health.’ HABITS AND LIFE HISTORY. The grevback beetles, although usually designated as cane-beetles, are by no means addicted to this crop, for, as investigation has demon- strated, they are apparently indigenous to the country. Hence they naturally exist in the uncultivated grass land; and from this, under some circumstances, they eventually spread into the cultivated areas, especially where these lie in proximity to suitable trees on which the beetles may feed. 14 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES That the beetles flourish in wild grass land is evidenced by Stockton paddock, near Innisfail. This grass area of 240 acres is a most interesting spot, since most of the money from their Cane Pest Destruction Fund is. spent for beetles collected there. Furthermore, strange to say, the surrounding canefields have not suffered from grub injury. While the writer was there in June, 1919, 1t was easily demonstrated by digging that grubs were abundant in this grass land; hence it would appear that that great mass of beetles was developed right here, year after year, alongside of the cultivated cane areas, without injuring that crop. Moreover, digging almost anywhere in grass land, at the proper season, especially where there is much of the so-called blady grass, discloses the erubs, even when far removed from cane areas; in fact, | have been told that they are abundant during their flight even up on the Atherton Tableland. Then, too, we now know that these beetles have an extensive range both up and down the coast; and they certainly are by no means limited to those sections that produce sugar-cane. Since grubs under natural conditions in uncultivated areas are seldom injurious to grasses, it would appear that man, by his serious. interference with the balance of nature, is mainly responsible for much of the devastation that is now resulting to his crop. This opens up an important subjeet, which will be treated in detail in a later section. EMERGENCE OF BEETLES. The beetles appear any time from October to February, depending entirely upon meteorological conditions. In fact they are frequently ready for months, waiting in their pupation chambers several feet below the surface for the soil to become sufficiently moist for them to escape. Thus, on 4th July, 1917, the writer found beetles fully 3 feet below the surface, in red voleanic soil so dry and hard that there was no hope of their escape under such conditions. That year the penetrating rains set in at the end of October, and the beetles came out in great numbers on 4th November. Hence the wait in the mature stage, without food, was just four months in this instance. And again, on 5th July, 1918, Girault found similar conditions at Greenhills; that year the beetles did not emerge until 25th November. After close observations for several years, it has been our experience that the beetles never appear in noticeable numbers until a few days after the first soaking rains, occurring any time between October and February. For instance, in the humid belts, such as the Babinda area, the beetles emerge fully a month before they do in the drier sections of the Cairns district. And, again, an extremely late emergence was that a Meringa during the season 1919-20; the rains did not begin until 15th January, 1920, and the beetles were not out in force until the 23rd of that month. Just after emergence the exit-holes of the beetles are very noticeable in the badly infested fields. These are about half-an-inch in diameter, and the tube is fairly clean. It is a problem what they do with the soil; the only explanation that occurs to me is that it is compressed into the surrounding walls as the beetles push their way to the surfaee. In November, 1911, Girault traced these tubes right down to the chambers, in each of which he found a cast pupal skin. After emerging the beetles usually climb up on to the cane, where they frequently take their first meal, as has been indicated above GREYBACK CANE BEETLE, LEPIDODERMA ALBOHIRTUM. 15 (Plate 3, fig. 1). Evidently they often remain right there for several hours—even until the next ev ening—for during the first few days of the flight it is not uncommon to find newly ‘emerged beetles rather abundantly feeding on the cane-leaves during the daytime. EVENING FLIGHT AND Matine HaAsits. All of our observations go to show that the principal flight of the greybacks from the cane to the feeding-trees takes place at dusk, usually between 7 and 8 p.m., and during this hour they do their mating. Just about 8 p.m. they all congregate and settle on the foliage of their favourite feeding-trees, where they remain very quietly until dawn. During the 1919-20 season Mr. Dodd was stationed at Greenhills, where he was able to keep the emerging beetles under constant observa- tion. He found that on leaving the cane they usually flew directly to the nearest feeding-trees, regardless of the direction of the wind; in that particular locality the forest feeding-trees were to the east and south-east with a small area of scrub further back. And again, during the past season (1920-21) we both spent most of our time early and late in the fields, so were able to verify former observations. It was not until this last season that we had made any definite observations on the mating habits of the greybacks. This was chiefly due to the fact that we had not gone after them properly, for we now know that copulation takes place repeatedly as lone as the beetles are on the wing, and that they are polygamous. In other words, it appears that the beetles mate repeatedly, evening after evening, beginning as soon as dusk comes on, during the w hole of their aerial existence, the males going from one female to another. Most peculiar is the fact that they continue copulating even when the females are packed full of ripe eges which are ready to lay. The reason that very little has previously been known of their mating habits is chiefly because these beetles favour large, tall trees, and often select those with thick foliage, especially for mating, even trees on which they do not feed, such as the mango, bamboo, milky pine, &e.; a fact which explains the clusters of beetles that may often be shaken out of these trees especially where lecated in the farmyards. The mating habits of Lepidiota frenchi and L. rothei, on the other hand, are easily observed, for they mate openly on low bushes, and even copulate while hanging on wire fences where other objects are not at hand. Where it occurs on the edges of serubs at Gordonvale it is usually sought after ; around Macknade Mill, in the Herbert River district, it is known as ‘the Beetle-tree,’’ which would serve to show its importance as a feeding- tree. The Candle Nut (Aleurites moluccana) is found sparingly in scrub areas, where it may attain a great height; both at Mossman and Cairns it was noticed to be attractive to the beetles; a very tall example near Meringa was drastically treated by them. Now follow the Figs; the three closely related Strangle Figs (Ficus infectoria, F. nesophila, and I’, pilosa) are taken conjunctly, since they are equally infested ; of these the first-named is most frequently met with. A large spreading tree of this species growing near Meringa, and separated from canefields by several hundred yards of bush, was completely stripped. In a patch of scrub a mile from the eastern border of the Greenhills estate there is a huge specimen of this parasitic fig; its aerial roots have enclosed several trees, forming a buttressed trunk many feet through, while the spreading head towers over its surroundings; in January, 1921, the branches of this giant were almost bare, while the ground beneath was covered with the excreta of the beetles. The ornamental Weeping Fig (fF. benjamina) and the Rubber-tree (2. elastica), which are cultivated in parks and gardens, are also highly favoured. The Cluster Fig (F. glomerata) oceurs near scrubs or along streams, and is a favourite food plant, being swiftly almost entirely denuded. Its ally, F. chretioides, is a rare plant around Gordonvale, but has been recorded as a feeding-tree wherever it was recognised, and has been observed strongly attacked. The foliage of another cultivated tree, the Jack-fruit (Artocarpus integrifolia), readily entices the beetles. Bananas, too, are greatly damaged, and Coconut Palms are almost invariably stripped bare. Little need be said of trees in the second class, but a few words on those of the third category may be worth while. The Mango has been recorded (66) as a food plant, and though this may happen occasionally our evidence is negative; trees have been watched where the beetles swarmed and mated meght after night, yet it could not be discovered that the foliage had been at all consumed; on account of its dense COMMON TREES IN RELATION TO AERIAL LIFE OF BEETLES. 43 leafage it yields splendid shelter for the beetles during the day. Girault and Dodd gave the River Cherry (Hugenia tierneyana), Leichhardt-tree (Sarcocephalus cordatus), and the Cockatoo Apple (Careya australis) as being occasionally attacked, but in our experience they can only be classed as harbouring trees. The Bamboo is often regarded as an important food plant; we are mindful of clumps of these in canefields, where the beetles swarmed in vast numbers each night, and yet investigation failed to show that the foliage had in any way been eaten. The third and fourth classes in the list are interesting in view of the fact that they show what common trees may be planted or let grow around homesteads, canefields, &¢., with a reasonable degree of impunity. ‘Of course, it 1s quite feasible that, with the absence of the usual feeding- trees, the beetles will turn their attention to those that are now con- sidered immune. One that we can commend highly as an ornamental and shade tree is the River Cherry (Eugema tierneyana) ; the glossy green foliage is very distinctive and gives splendid shade, and the prolifie crops of cherry-like fruit can be used for making very good jam. Perhaps the most interesting feature in a study of the feeding-trees is the obvious discrimination in the choice of food that the beetles exhibit, even between trees that are closely related. A striking example of this power of discernment is observed in the Wattles; among others, two species occur in great profusion in the Cairns district—namely, the Black Wattle (Acacia aulacocarpa) and the Cream-flowered Wattle (A. flavescens) ; the former has not under any circumstances been recorded as being eaten, while the latter is one of the most important feeding- trees. A yet more forcible case is instanced in the various forms of the Paper-barked Tea-tree (Melaleuca leucadendron), one variety of which is highly favoured by the beetles, the other three apparently being immune. Six members of the genus Hucalyptus thrive in the neigh- bourhood of Gordonvale; one, the Moreton Bay Ash, is more readily attacked than any other tree; four are more or less preferred; and one, the Poplar Gum (F. platyphylla), is palpably distasteful. In this family (Myrtacex) there are two exceedingly common trees in this same district, the Swamp Mahogany (Tristania suaveolens) and Cockatoo Apple (Careya australis) ; both of these are everywhere to be noticed in the forest areas, but neither suffers invasion. Then, too, in the genus Glochidion, one species is much fancied, the other, to our knowledge, not being appreciated (of this second species, G. lobocarpus, Tryon records that ‘‘it is also attacked by the beetles,’’ although we have not found such to be the case). Finally there are the various Figs; no dis- crimination seemingly is made between the several Strangle Figs; the rough-leaved variety (I. opposita) is eaten intermittently, but some of the smaller kinds that are rarely more than shrubs, as /’. magnifolia, F’. casearia, and F’. hispida, would seem to escape aggression. The knowledge that cane-leaves are sometimes eaten leads to the interesting surmise that if the forests were cleared away it might be possible for the beetles to subsist entirely on this foliage. However, considering the myriads that breed in eanefields and the immense number of females that return to deposit their eggs, it is not surprising that a few individuals have acquired the habit of dawdling there for a day or so to eat; it has been found that these stragglers were invariably newly emerged, or females re-emerging from the ground after egg-laying. We are indebted to Mr. C. T. White, Government Botanist, for the determination of the plants in the above list. Lepidiota frenchi Blackburn. This species was named by the late Rev. Canon Blackburn, and the description appeared in the Transactions of the Royal Society of South Australia, vol. xxxvi, 1912. The type locality was given as ‘‘ Queensland (Cairns) ; male from Mr. French, female from Mr. Lea.’’ As to the distribution of this species, Girault and Dodd (66) included Mossman, Cooktown, and Babinda. But by carefully breeding out the grubs Mr. Dodd (91) found that those from Cooktown were Lepidiota No. 683, a species later named consobrina by Girault; and the Babinda grubs proved to be Lepidiota caudata Blackburn. Mr. Jarvis, however, probably overlooked these data, for he (99) based his conclusions upon the unverified records published by Girault and Dodd. Subsequent observations go to show that this species belongs essentially to the open forest country, favouring areas well supplied with the native grasses: it has never been collected in the densely timbered serub lands. Then, too, as far as we have been able to observe this species occurs only at Mossman, outside of the Cairns district, where its chief centre of action is about Gordonvale. IMPORTANCE AND NATURE OF INJURY. Though the range of this species is apparently limited, the individuals sometimes emerge in tremendous numbers, and their offspring, the grubs, frequently do considerable damage to sugar-cane. Indeed, in their range, they are considered almost as destructive as the larger greybacked species. This is largely due to the fact that the grubs live almost two vears in the soil, the very destructive third stage requiring fully a year to mature. Furthermore, these large grubs are able to start activ ities on the cane- roots in August or September, several months before the eges of the gereybacks are laid; hence their work at this season is particularly noticeable, especially on the late-planted crop. My first experience with this pest was in a first ratoon crop of Badila near Gordonvale, in November 1917. As many as twenty-five large stage II] grubs were found under a stool, near the grassy roadside, while further back in the field the average per stool was only five to eight. The infestation appeared to be in patches, a chain or so in extent, and these were more prevalent near the grassy borders of the field. About the same time I discovered plant cane suffering in a similar manner on several other farms near Gordonvale. In eae ‘h case there was the same spotted appearance in the fields, comparatively small areas here and there being practically killed out, whilst adjoining cane was nice and green. The injury was particularly bad in a field where grass had been ploughe d out preparatory to planting the crop. The erubs had eaten off all the roots of the young plants, and in some cases had bored right into the old seed-stalk, where we found them at work; in other instances they had cut off the young shoots, just as is the habit of the greybacks. November, 1918, I found this species giving considerable trouble at Mossman. One ratoon field at the edge of town, though yellowed in patches by them, was not killed out; this was apparently due to the fact that the grubs were more abundant under bunches of grass that grew in the centres than they were in the cane itself. At Mowbray, too, in that district, I found this pest; it had killed out plant cane wherever it occurred on high spots in the field; moreover, cane in the low places was LEPIDIOTA FRENCHI. 45 beautifully green, with no indication of grubs. Evidently, the beetles in their flight had bumped into these knolls, just as has been observed in the case of our other species. HABITS AND LIFE HISTORY. Emergence and Mating—Though this species has a two-year life- cycle, there is a considerable emergence every year. Usually a day or so after the first heavy rains of November or December have soaked the hard subsoil the beetles come out in hordes. When in a grass paddock at dusk, they appear to rise right from under one’s feet, and on every side, in a seething swarm. After a wild flight of about ten minutes, they begin to settle on any convenient low objects, and mating takes place. The females always settle first, but each is quickly surrounded by several males; when one is attached the others fly away. The attached male always lets himself fall back as soon as union is secured, and hangs head downward supported only by the genitalia. So abundant are these mated couples that in places where they are unable to find sufficient low bushes they cover the fences, even hanging on the wires. Apparently their main concern is to mate immediately after emerging from the ground, night after night; this is kept up, as we have been able to demonstrate, during the whole period of their aerial life, which lasts for two or three months. In a field of sugar-cane one really has a better opportunity to observe this mating flight. Half an hour after sunset swarms of beetles rise out of the ground simultaneously, on every side, when they begin flying close over the tops of the cane in great circles, as wide as the eve ean see. The flight is much swifter than that of the larger greybacks and more direct, with no regard to any ordinary breeze. In dashing along so close to the tops of the cane they constantly strike against the leaves, producing a series of sounds very noticeable above the constant hum of the seething swarm. After flying for a few minutes, the females settle on the cane-leaves, and mating takes place, as has already been described. Since the duration of this act had never been definitely recorded, some attention was given to it. We found that there was little regularity in the time that they remained together, this ranging anywhere from twenty to twenty-nine minutes. Most of this time they were perfectly rigid, and remained so even when held in the hand. Near the completion of the act the male invariably began a movement of his legs, as if trying to escape, and finally set his wings in motion; then pulling himself loose, he flew away to the feeding-trees, leaving his mate in the cane. These beetles, lke the greybacks, have two definite flights each day—morning and evening; they differ, however, in that they spend the dav in the soil, and eat comparatively little. The evening flight, which is primarily for mating, has been briefly described above. Field observations, on numerous occasions, all go to show that these beetles feed but little during the mght, for they are usually found huddled up as if stiff and cold, when observed with a lantern. The morning flight begins just about half an hour before sunrise, when it is broad daylight. Beetles observed on the foliage at about 5-30 a.m. appeared to be stiff and lifeless. A few minutes before the flight started, however, each began to move the head and end of the abdomen. The antennex were thrust far out, the plates extended, as if trying to sense the surroundings. In a moment the legs and wings began to move as they rose high on their toes and were off on their mad whirling flight. After about ten 46 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. minutes or so, they began to settle on various stems, either dry or green. from 6 to 12 inches above the ground, and always with the head upward. In this position they remained perfectly motionless, with antenne extended, for a short period of one to several minutes, when they turned and walked quickly to the ground. In an exceptional case, I saw a beetle wait twenty-five minutes before descending to enter the soil. Apparently there is a marked homing instinct among these beetles, for. in every case but one, those that I saw came to rest on twigs with a definite exit-hole at the base; and in most cases they crawled directly into this when descending. In the exceptional case, noted above, the beetle landed on a dry stick which was hanging but not reaching the ground. When he came to the end in his descent he appeared to be mystified, for it was still 6 inches to the soil; he turned round and climbed up, then came down again, reaching as far as he could below the end ot the stick, as if trying to reach the ground. Still not satisfied, he climbed up a few inches, and when he came back down to the broken end he opened his wings and cireled around to another stick, evidently the right one, for it had an exit-hole at the base. After reaching the ground the beetles are often satisfied to simply get their heads covered in the hole. | have seen them with the hinder part of the body still exposed to view, even up till 8 a.m.; when the sun Fegan to warm up they dug in. This tardy habit of entering the soil is surely very detrimental to the species, for it exposes them to their natural enemies, both birds and parasites. In fact, on one occasion I observed a flock of ibises feasting on them shortly after the morning flight. The birds poked their long slender beaks into the grass at the base of each of the stems, and in most cases they got the beetle. Exeavation, on numerous occasions, showed that where the beetles enter the soil to hide during the day they do not go deep; usually those located were at depths of 4+ or 5 inches. Observations on the morning flight in fields of sugar-cane were very similar to those recorded above. Before the flight begins the beetles are to be seen sitting about on the leaves; they go through the same preliminary preparation of sensing the surroundings, and they have the same circling flight close over the tops of the plants, that I have noted in the evening’; but their movements are so swift that it is difficult to observe any single specimen long. When ready to alight on the cane, they fly in small circles, and appear undecided just where to land; they then rest on the leaves for a few minutes, and fall to the ground. I watched three specimens after they were on the ground, and it was fifteen to thirty minutes before they began to dig in, and in each case they crawled under the stool first, burrowing near the roots. Like the ostrich, they stuck their heads in, and then remained quiet for about fifteen minutes before burrowing deeper. About 6-30 a.m. the sun was getting on the ground; nevertheless, | could still see a part of the tail of each beetle at 7 a.m., so I marked the spots. At 2 p.m. we tried to dig them out, but only found one, though we went down a foot. This one proved to be a male, and was 4 inches straight down from where he entered the soil. Evidently the other two were gravid females, for, as I learned subsequently, these go deep to Gviposit. Though these beetles remain exposed so long after the morning flight ceases, it is an exceedingly difficult matter to find them, for they are so much the colour of the soil, especially on the red volcanic lands. LEPIDIOTA FRENCHI. 47 Feeding Habits and Food Plants——In their native habitat, in the open forest, these insects usually feed on the foliage of the Moreton Bay ash and bloodwood, but where they occur in fields of sugar-cane far removed from these trees they have evidently been able to change their habit, deriving what little food they require directly from the cane-leaves (Plate III, fig. 2). I have gradually come to this conclusion because the beetles continue to infest certain fields near Gordonvale after all possible feeding-trees have been cleared away. And, as further evidence, I have found the beetles on the cane during the night, and they are there on the same leaves very early in the morning when they fly and re-enter the soil. Only occasionally, however, is there any indication that they have eaten the leaf upon which they have been sitting during the night. These observations, coupled with the fact that the alimentary canal is usually found nearly empty when beetles are dissected, point to the conclusion that they require much less nourishment than do the greybacks. Ovipositing—During the season 1920-21 I was able to give much more attention to this important phase of the subject; thus a considerable mass of data has been added to our files. In the present paper I will be able to summarise only the more important of these. Most important, perhaps, is the discovery that the females of this species apparently have the eggs well developed and almost ready to lay when they emerge. Then, too, we have never known before that they continued to lay one set after another, during the whole of their aerial existence. And we had no definite knowledge of how or where the eggs were deposited in the field. 30th November, 1920, I dissected a lot of females of this species, and was surprised to find the eggs in every case nearly ripe, since the first emergence had occurred only two days before. The egg-tubes were dissected out, and I found that the general appearance of the ovaries was very similar to that already described for the greybacks (sce Plate IV). Each of the tubes usually had two developed eggs and a smaller one; hence it would appear that at least twenty-four eggs would be laid in a set. I made a camera lucida sketch of one of the tubes, which showed an egg already passing downward to be laid (Plate XIII, fi Di) ), oth December, | made further dissections of beetles taken in cop., and, as I expected, found that some of them had evidently laid, although this was only a week after the first emergence had been noted. The ovaries, in such cases, had a peculiar appearance, and the ege-tubes were considerably shortened (Plate XIII, fig. 3). In other specimens the eggs were still retained, but in some they had passed down the fubes: (Plate XIE, figs 1): 13th December, sixteen females taken in cop. were dissected, and evidently fourteen of these had laid, for only two contained ripe eggs; all the others had practically empty egg-tubes. 26th December, mating beetles were more abundant than usual. so I dissected thirty-eight females taken in cop. Among these I found the first conclusive evidence that the females continued their activities after they had laid their first batch of eggs. Twenty-one of this lot had empty egg-tubes, and in most of these the body-fat had been absorbed, and the alimentary canal almost invariably contained only a dark-coloured liquid, with no solid food. Furthermore, in one case there was a single ripe egg in the vagina, while all the ege-tubes were empty, except for co) the small ova next to the germaria. This proved definitely that they continued to mate after laying, and suggested that they probably would 48 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. produce more eges before succumbing. Only eight of these thirty-eight specimens contained ripe eggs; the remaining nine had ova in various stages of development. 27th December, I dissected the females of forty-seven pairs taken in cop. on cane-leaves, and found that forty-two of them had_ laid, though fifteen of this number had begun to form new sets. The remaining five had ripe eggs, in the following numbers: 22, 31, 35, 35, 34, an average of 31-4 eggs each. 5th January, 1921, the beetles continued in tremendous numbers, so that the mating pairs covered the posts and wires of the fence. I dissected seventy females taken in cop. They had all evidently laid; but fifteen of them were almost ready to lay again; of the balance, thirty-five had new sets well started, and twenty had evidently laid a second time, for their ovaries were practically empty. 29th January, mating still continued as usual, the pairs hanging thickly in low bushes, but the numbers were considerably reduced, so that they were not found on the fences. Twenty mating females were dissected, and I found ten of them with nearly empty egg-tubes, showing that they had recently laid; five had sets started with about one egg in each tube, half-size; the other five had eggs ready to lay again as follows: 15, 5, 15, 14, 15. With this information we knew definitely that the beetles continued to mate and produce eggs as long as they lived. As to the number of ege’s laid we can only conjecture, since they do not act naturally in confinement. Yet it 1s safe to assume that several sets are produced, for the beetles are usually on the wing for two months or more. Many beetles were placed in cages with soil during the period of their abundance, in an attempt to study their laying habits. In some eases they were supplied with fresh leaves of Moreton Bay ash or bloodwood daily, and in others kept without food. Interesting observa- tions were also made by keeping the beetles enclosed in soil, so that they could neither come to the hght nor feed. 4th December, 1920, many pairs of beetles taken in cop. were confined in cages containing sail, with hght above; half of these were fed and the others starved. 11th December, the cages had been cared for daily; the beetles were always found beneath the soil, and, in the case of those with food, slight evidence of eating was obtained. On this date one of the beetles, No. 4, without food, had deposited four eggs, loosely and singly in the soil. 15th December, this same beetle (No. 4+) deposited fourteen more eges; they were placed singly as before, each apparently in a small walled chamber. One of the beetles supplied with food, No. 1, laid two eggs. 18th December, the beetle in cage No. 1 had laid two more eggs. Another of the starved beetles (No. 3) laid twenty-three eggs, loosely and singly in the soil as above. 20th December, beetle in cage No. 3 laid another egg, and No. 4 had laid five more eggs. 23rd December, beetle in cage No. 1 laid eleven more eggs. Beetles dead in eage No. 3; total eggs twenty-four. In cages Nos. 7 and 8, without food, beetles dead, with no eges. After seventeen to twenty days the beetles without food died; those LEPIDIOTA FRENCHI. 49 with food were alive. Three of the dead beetles were packed full of ripe eggs. When.the food was daily changed it was found to be sparsely mibbled. 30th December, the beetle in cage No. 1 had laid seven more eggs. Beetle dead in cage No. 4; total eggs twenty-three. 6th January, 1921, beetle in cage No. 1 dead; total eggs laid twenty- two. Dissecting this specimen, five ripe eggs were found in the ovaries. The beetle in cage No. 5 with food was also dead; she had thirty ripe eggs in the ovaries; none had been laid during her confinement of thirty-four days; possibly the small space upset her. 10th January, the beetles dead in the remaining cages, with no eggs in the soil, though dissection showed large complements in the ovaries. The longest life in confinement with food was 38 days, average 25-66 days; without food, average 17-33 days. Numerous experiments along this same line were carried out by Mr. Dodd, but the general results were not very different. The number of eggs obtained was very small; but dissection of the beetles indicated that they must have laid their first set before capture. Still, as several of the dead beetles when dissected, and that had not laid at all in confinement, were full of ripe eggs, it must be presumed that the unnatural conditions were felt by them. Confined conditions cause them to retain their eggs, and they may die still withholding them. The eggs were all fertile, even those laid right up to death; therefore the absence of the male does not interfere with their development. Confined space did not appear to have any influence on the length of life. The last beetle died 55 days after capture, and had been eating up to within a few days of death. The difference in the length of life of those supphed with food and those starved is not great. The average for the former was 38 days, for the latter 29-3 days. Thus, apparently unhke Lepidoderma albohirtum, the adults of this species that have once fed can live for ¢ long period when starved, and successfully develop eggs. Hence this may have an important bearing upon their distribution, as has been suggested above. In order to learn how the eggs were deposited under natural conditions, I employed the same method that I used for the greybacks. Two gravid females were collected at the end of the morning flight, in a canefield, and placed in a large cage in the garden and supplied with males. They at once entered the soil. In the evening I watched the cage, and was rewarded by seeing the beetles emerge from the soil about 7 pm. At the same time several males arose from the grass near-by and clustered around the cage. After three days I examined the soil under the cage for eggs, with very satisfactory results. A trench was first dug outside the cage, and the soil was gradually shaved off the face of this until I found eggs at a depth of 8 inches. Each egg was in a well-defined, tiny oval cavity, about 5 millimetres long and less in width. The ten eggs in this set were placed rather close together, some of the cavities being not more than + inch apart. About 6 inches away I came upon another small set, at about the same depth. In this case I could find only five eggs. It is a very difficult matter to find the eggs, especially if the soil is damp, for each egg is enclosed in a small pellet of earth about $ inch in diameter. D 50 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. IT came upon the third set about 5 inches further in and 10 inches deep. Only nine eggs could be found; these were right down in the hard yellow-clay subsoil.