288 On the Larva of a stipposed (Estrus Hominis. 



ferent changes of the insect might have been observed, and our 

 knowledge of the species completed. As it is, we are ac- 

 quainted with the larva alone. Its description is as follows : — 

 Length, in its present shrivelled condition, seven-tenths of an 

 inch ; circumference round the centre or thickest part one inch ; 

 colour pale dingy apple-green, tinged with brown. The mouth 

 appears to have been somewhat tubular, but is furnished on its 

 upper part with a pair of sharp minute hooked crotchets, of a 

 shining black colour, probably for the purpose of adhering more 

 firmly to the spot from which it was desirous to draw its food. 

 The eyes are large and prominent ; their colour brown. The 

 body is composed of nine rings or segments, exclusive of the 

 head and anal portion. There are thus, in all, eleven segments, 

 besides the mouth, the exact number of which the larvae of the 

 European species consist. There are no feet. These organs 

 are, however, obviously supplied by transverse circles of small 

 black spines or hooks, with which the principal segments of the 

 body are furnished ; and, besides these, there are several rounded 

 unequal protuberances on the back and sides. The latter are 

 possibly produced or rendered more apparent, by the decrease 

 of size which has taken place. Supposing these minute spinous 

 hooks to be, along with the skin, under the control of muscu- 

 lar action, (and Lyonnet has beautifully exhibited the compli- 

 cated muscular structure of another larva), then, according to 

 the direction in which the hooks are pointed, a wriggling mo- 

 tion would produce either outward or inward progression, and 

 serve all the purposes of locomotive organs, just as (to use a 

 familiar illustration) an ear of barley placed within the sleeve of 

 a pedestrian, works its way in a direction opposite to that to- 

 wards which its beard is directed. 



Larva of (Estrus Hominis. 



