302 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
beetle (Epicauta), which passes through three larval stages before 
transforming to a pupa. He divides the life-history of this beetle into 
the following stages: (1) Triunguliu; (2) second larva (a, Carabidoid; 
b, ultimate or Scarabaeidoid stage) ; (3) pseudo-pupa, or coarctate larva ; 
(4) third larva (closely resembling the Scarabaeidoid stage of second); 
(5) true pupa ; (6) beetle. (The reader should examine the figures in PI. 
IV of the First Report; otherwise he cannot understand the following 
remarks.) 
It appears, then, that the first larva, or triungulin, in form resembles 
the Campodea-like primitive larval form of Coleoptera ; the Epicauta 
triungulin closely resembles a Oarabid larva, the head, antennae, and 
mouth-parts, as well as the legs and form of the body in general, being 
on the primitive, Oarabid type (somewhat like Casnonia ('!), Galerita 
and Harpalus); the second larva, a, Carabidoid stage, though quite 
different as regards the mouth-parts, and with a smaller head, thicker 
body and much shorter legs, still adheres to the higher Oarabid form 
(Oarabus and allies). During the Scarabaeidoid stage the second larva 
rests nearly motionless in the egg of the locust, and is like the curved, 
clumsy larvae of the cockchafer or June beetle and other Lamellicorn 
larvae, which also have the similar habits of lying still in their bur- 
rows and feeding on the roots of grass, or, as in the case of Osrno- 
derma, lying nearly motionless in their cells in rotten wood. This sort 
of life going on, the larval blister beetle after six or seven days assumes 
the ultimate stage of the second larva, and now, from apparent con- 
tinued disuse, the mouth-parts and legs become more aborted than 
before, and the insect in this stage may be compared to some Lon- 
gicoru larvae, with a general resemblance in the curved, cylindrical body 
to the Ptinid and Chrysomelid, and it even approximates in general shape 
Curculionid larvae. In the pseudo-pupa or coarctate larva this process of 
disuse and obsolescence of parts culminates in the immobile stage pre- 
ceding (with the intervention of third larva) the pupal condition. We 
thus see that in the life-history of a single species of beetle, change in 
habits or environment, as well as in the food, induces change in the form 
of the body ; and this series of changes in the Meloidao typifies the suc- 
cessive steps in the degradation of form which characterize the series of 
Coleopterous larvae from the Oarabidae down to the Curculionidae and 
Scoly tidae. At first all larvae were carnivorous and active in their habits, 
with large mandibles and well developed accessory jaws and legs; cer- 
tain forms then becoming scavengers, their appendages became, from 
disuse, less developed; then others, becoming phytophagous, became in 
some cases still less developed, the jaws shorter and toothless, with cor- 
responding modifications in the other mouth-parts, the antennae and the 
legs, while the body became thick, fat and cylindrical; until in the wood- 
boring and seed- or nut-inhabiting weevils the antennae and maxillae be- 
came rudimentary, almost disappearing, while the legs utterly vanished. 
Change of habits and surroundings, with corresponding changes in the 
