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THE AMERICAN ENTOMOLOGIST 



The ground that was first filled with locust 

 eggs by the (Kdipoda atrox by the end of Septem- 

 ber, looked as if scattered with loose shells, so 

 thorough was the work of destruction. 



A few of the grubs were detected in among the 

 eggs in April, but not generally until August. 

 One individual seems to empty several egg-cases 

 before retiring from the feast and coiling himself j 

 up in a case which he has emptied, or in a nidus 

 of his own make. — J. G. Lemmon in letter to C. j 

 V. Riley, Oct. 12, 1879., 



During 1878 and 1879 we failed to rear 

 any of them to the perfect state, but on June 

 20, of the present year, 1880, we obtained 

 from these California larvae the first fly. 

 This proved to be a male of Triodites nius 

 O. S.,* as kindly identified for us by Mr. S. 

 W. Williston of New Haven. The delay 

 in the printing of this report enables us to 

 complete the natural history of these in- 

 sects. We have, during the summer, reared 

 many additional specimens of this species 

 and also of the Systcec/ius areas already 

 alluded to. Prof. Lemmon and his 

 brother, Mr. W. C. Lemmon, have also 

 succeeded in obtaining the mature flies 

 and have observed this Systoechus abund- 

 antly buzzing about over the ground 

 in which the locust eggs were laid, as the 

 following extracts from the correspondence 

 of these gentlemen will show : 



An enemy which has proved very destructive 

 in Sierra Valle}' and vicinity is the larva of, as 

 yet, an unknown insect. It is first observed as 

 a large, yellowish-white grub, about half an inch 

 or even three-fourths of an inch long when ex- 

 tended, it being usually curi^ed so that the head 

 and tail nearlj' touch. It is one-sixth to one- 

 fifth of an inch thick just back of the head, and 

 tapers slightly toward the tail ; also flattened 

 slightly dorsally. It is usually found in a case 

 of locust eggs which it has devoured, pushing 

 the empty shells aside, and at last occupying the 

 space where were 21 to 36 eggs. Often it is 

 found in a little space below anumberof emptied 

 cases as though it had feasted off the contents of 

 several nests. 



The grub was first noticed last April 20th in 

 the egg deposits near Loyalton. This Fall, 

 Sept. 7th, it was detected in great quantity near 

 Sierravillc, and afterwards in several infested 

 spots of the valley. A handful of such soil will 

 generally display ten to twenty cases of locust 

 eggs, more or less emptied, and half as many of 

 the fine fat grubs. — J. G. Lemmon, in the Sacra- 

 mento, Cal., IVeeldy Record i'mon, Nov. 29, '79. 



The white grubs ate out and destroyed thous- 

 ands of the eggs last Fall, but to all appearance, 

 have eaten nothing since, having lain dormant 

 all winter, and being now found still among the 

 eggs which are fast hatching out.— W. C. Lem- 

 mon, Sierra Valley, Cal., June 13th, 1880. 



Western Diptera, p. lilti. 



I send to you by this mail another package of 

 the locust-egg-eating grubs, some of which you 

 will find more developed. My brother. Prof. J. 

 G. Lemmon, came up from Oakland day before 

 yesterday to spend a few days, and while looking 

 at the grubs that I had gathered for you yester- 

 da}', one of them developed into the Humble-bee 

 fly which 3'ou have bred and a half dozen speci- 

 mens of which I have caught and envelop 

 rolled up in paper. — W. C. Lemmon, in letter 

 to C. V. Riley, from Sierra Valley, Cal,, July 18, 

 1880. 



■ Happening home on a hurried visit I find lo- 

 custs and destruction all around, — a sad, sad 

 sight ! Find my brother has tried to keep you 

 posted up with specimens and notes. Am 

 pleased to see a solution of the " big white grub " 

 question. He develops into a species of fly, 

 hosts of which are now seen in mid-day buz/ing 

 about among the locusts. — Prof. J. G. Lemmon, 

 in letter to C. V. Rilev, from Sierra Valley, 

 Cal., July 18, 1880. 



This habit in the larvae of Bombyliids 

 of preying on locust-eggs has not before 

 been suspected, and in this connection we 

 will review what has hitherto been known 

 of their habits : 



Prof. J. O. Westwood has given in the 

 Transactions of the Entomological Socie- 

 ty of London (1876, pp. 497, 498), the fol- 

 lowing observations upon the larval habits 

 of Bombilii : 



Thanks to the researches of previous observers, 

 the economy and transformations of the Bombylii 

 are now satisfactorily known to entomologists, 

 Latreille rightly considered that the Bombylii, 

 like Anthrax, were parasites, contrary to the opin- 

 ion of Zetterstedt that the larvae feed on the 

 roots of plants (Ins. Lapp., p. 510). The pupa 

 of Bonibilins .major was first figured bj' M. Im- 

 hoflf in the Isis for 1834, having been found by 

 him in a situation which he had previously no- 

 ticed to be frequented by Andrena humilis (vol. 

 1834, p. 536, pi. xii.). In my Introduction (vol. 

 2, p. 538, 1840), I published a figure of the same 

 pupa from a specimen discovered by Mr. C. 

 Pickering in a sandy gravel pit at Coombe 

 Wood on the 28th of March, from which the 

 imago was produced in a few da3's. The pupa is 

 verj' similar to those of the species of Anthrax, 

 which are known to be parasites, having the fronts 

 and underside of the head armed with strong 

 spines, and the dorsal segments of the abdomen 

 furnished with transverse rows of strong reflex- 

 ed booklets. In 1852, M. H. Lucas published 

 the description of a new Algerine species of the 

 genus. Bomb, bogharicnsis in the Annales of the 

 French Entomological Society, 2nd ser. vol. x., 

 p. II, pi. I, No. II, which he had reared from a 

 pupa found under a stone in a damp, sandy sit- 

 uation, and, contrary to the opinion of Latreille, 

 he expressed himself thus : "je suis porte a 

 croire que les larves qui composent ce genre ne 

 sont pas parasites, comme le supposent Latreille 

 et beaucoup d'autres Entomologistes, mais qu- 

 elles vivent au contraire isolement dans la terre, 

 — opinion, au reste, qui avait deja ete emise, 

 mais avec doute, par M. Macquart, et que men 

 observation vient confirmer." 



