CHAPTER IV. 



THE LARVA OF THE BLOW-FLY, 



1. EXTERNAL FORM AND SEGMENTATION. 



External Form. — ^The larva of the blow-fly is well known as 

 the gentle or maggot. It is a soft-skinned, cylindrical, wedge- 

 shaped worm, gradually increasing in diameter from before 

 backwards, and truncated behind obliquely, so that the pos- 

 terior extremity exhibits a concave surface, which looks upwards 

 and backwards, within which the great posterior spiracles are 

 situated. 



Bibliography. — Papers on and references to the larvie of various Dipterous 

 insects are very numerous, but those which treat on their anatomy are few, 

 and usually short. The majority are descriptions of external form and habit. 

 Brauer [14] gives 47 quarto pages of bibliography, arranged under genera 

 and species. The CEstrida;, the larvse of which differ little from those of the 

 Muscid^e, have been chiefly studied ; and Brauer, in his monograph on the 

 family, gives a full bibliography to 1861. 



Special references to papers on several organs are given under the sections 

 of this chapter. 

 V 16. BOUCHE, 'Beitrage zur Insectenkunde.' i. Bemerkungen iiber die 

 Larven der Zweifli.igligen Insecten. Nova Acta. L. C. Acad. 

 Bd. xvii., p. 495. (1833) 1835. 

 \y 17. Schroder, van der Kolk, ' Memoire sur I'Anatomie et la Physiologic 

 du Gastrus equi,' avec 13 pis. Verhand. d. Kl. Xederl. Inst., 

 D. ii., p. 1-155. 1845. 

 V/ 18. DUFOUR, Leon, ' Etudes Anatomiques et Physiologiques sur les 

 Insectes Dipteres de la famille des Pupipares.' Ann. Sc. Nat. Zool., 

 ser. iii., torn, iii., 1845. 

 Ny 19. DUFOUR, Leon, ' Recherches Anatomiques et Physiologiques sur les 



