2IO MAINE} AGRICULTURAL EXPERIMENT STATION. I916. 

 III. THE SHORT-TAILED FILTH-INHABITING TYPE OF LARVA. 



Body cylindrical with the anterior segments modified into a 

 "false-head." Posterior respiratory process short, the spiracles 

 convoluted and denticulated. Inter-spiracular ornamentation of 

 short, palmately-branched, plumose hairs. No external mouth- 

 parts but a chitinized mouth-hood. Three pairs of lateral, 

 fleshy, conical protuberances on segment twelve. Segmental 

 hairs triple or quadruple, flexible, inconspicuous. Rudimentary 

 prolegs. " Pupal respiratory cornua prominent, morel-shaped. 



This type of larva is superficially like the Boring Type, but the 

 anterior three or four segments instead of being accuminate are 

 rounded out, globose, as broad as, or broader than, the succeeding 

 segments, and somewhat separated from them by a slight neck-like 

 constriction to make a kind of false head. There are no external, 

 chitinized mouth-parts, the mouth opening being covered by a mod- 

 erately-chitinized, striated mouth-hood, the termination of the cephalo- 

 pharyngeal skeleton ; and guarded on each side by a poorly defined, 

 piliferous fold of skin.' 



The posterior respiratory process shows its origin from two tubes; 

 the circular plate is on a- level with the apex of the tube; and the 

 slit-like spiracles which are more prominent are convoluted and also 

 ornamented with more or less numerous lateral projections or denti- 

 cles.' The inter-spiracular ornamentation consists of. plumose, pal- 

 mately-branched hairs. The segmental vestiture' consists of clumps of 

 about three or four fine, flexible hairs, a little longer than the ihte- 

 gumentar vestiture, and all arising together. The larvae have seven 

 pairs of prolegs along the ventral side of the body, which consist of 

 elevated folds of the body-wall over which the integumental vestiture 

 is specialized into heavier, rigid and retrorse hooks of varying size. 



This and the following types of larvae differ strikingly from the 

 first in producing for the pupa stage a pair of very conspicuous tubular, 

 anterior respiratory cornua, studded with minute nodules : and' con- 

 nected with the hymphal prothorax, as in the first type, by large 

 tracheal trunks. These cornua in the three species examined are more 

 or less mushroom- (morel-) shaped. 



IV. THE LONG-TAILED (RAT-TAILED) FILTH-INHABITING TYPE. 



Body cylindrical with a false head, and long tail. This 

 posterior respiratory process elongate, telescoping, flexible, at 

 least half as long as the body. The spiracles on its end entirely 

 inconspicuous. Inter-spiracular ornamentation of single, long, 

 plumose hairs. No external mouth-parts except the mouth- 

 hood. Segmental hairs double or triple, flexible, inconspicuous. 



