GROUND-BEETLES THAT ATTACK LOCUST-EGGS. 291 



1877, preying on the locust eggs, especially in Minnesota ; and the fol- 

 lowing letters from Mr. Seth H. Kenney, of Morriston, Rice County, 

 Minnesota, through whose kindness we have been able to study all its 

 transformations, have reference to it : 



I herewith send you some grubs, such as have eaten large quantities of grasshopper 

 eggs, and have extended all over our farms in this vicinity. I have found them eating 

 the eggs, and where the eggs were laid most plentifully there the grubs are the thick- 

 est. I send you by mail two boxes, one full of soil, and quite a quantity of eggs and 

 live grubs of all sizes, and some that have evidently begun to change into the beetle. 

 The ground is dug and thrown to the surface by these grubs ; and I send some of the 

 soil as they throw it up, because it is singular. How they could become so plentiful, 

 unless the eggs that make them are laid with the locust eggs, it is difficult to conceive. 

 — [May 12, 1S77. 



The ground where these beetles occur is full of holes, from 4 to 6 inches deep, and 

 just large enough to admit thom. lS[ow, I find no pellets near these holes, and I there- 

 fore conclude that the beetles do not make the pellets, but that the grubs do. I kept 

 some beetles in a glass vessel with some grass over Sabbath, and when I examined 

 them they had fought and devoured each other, until only one and the fragments of 

 three were left. — [June 11, 1877. 



The eggs must be laid during the summer months, and the larv?e 

 which we have found of various sizes, but principally full grown, as late 

 as Kovember, must often hibernate and feed for awhile again in spring. 

 In this, however, there will be found no regularity, and some of the 

 more advanced larvsB doubtless produce beetles in the autumn, as the 

 beetles of the genus are often found hibernating. The pupa (Fig. 25, h) 

 is formed in a simple cavity in the ground, and lasts in midsummer from 

 two to three weeks before changing to the beetle. 



Authors differ as to the food-habits of the beetles of this genus, some 

 believing these are phytophagous, others that they are carnivorous. 

 The facts here recorded leave no doubt as to the carnivorous propensities 

 of the species in question, and they are in accordance with the general 

 habits of the family. It by no means follows, however, that the beetles 

 may not at the same time be plant-feeders also, for we have good author- 

 ity that a species {Zxhrus gibhus, Fabr.), belonging to an allied genus, is 

 at times quite injurious to wheat, while Mr. Zimmermann,^^ in a valuable 

 memoir on the genus, shows that tiaey feed upon the pith and stems of 

 graminese and on succulent roots as well as on soft insects. Indeed, the 

 two habits are much more often combined than entomologists generally 

 admit. 



The beetles of the genus generally hide during the day under stones, 

 clods, grass, &c. The habit of the larvse, noticed by Mr. Kenney, of 

 throwing up little pellets of earth, is quite curious, and we can only ac- 

 count for it by the soil being unusually wet and adhering to different 

 parts of the body, from which, in being detached, it gets rolled by the 

 jaws into the pellets mentioned, which are irregular in shape and aver- 

 age about 1.5™™ in diameter. 



Amaha OBESA. — Larva. — Color dull whitish ; heaviest and widest about the middle 

 of the body, tapering rather suddenly from joint 10; head, and prothorax above, gam- 



^liev. Ent. de Silbermann, II, p. 189. 



