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MR. J. G. H. FREW OX THE LARVAL 



Summary. 



The external and internal anatomy of the niatiue larva of 

 Chlorops tcemopus are described in detail. 



The external anatomy of the first and second larval instars is 

 compared with that of the third instar and points of difference 

 noted. The pnparium and the egg are also described. 



The external anatomy of the third larval instar and the 

 puparium of Jlleromyza nigriventris and of BaUoptera comhlnata 

 are described and compared with the corresj)onding stages of 

 Chlorops iamiopus. 



The winter host-plants of the three species are given, together 

 with a. list of eleven grasses whicli have been examined but do 

 not serve as winter hosts for any of the aViove species. 



Heferexce Lettering of Text- Figures. 



a. antcnnn. 

 a.sj>, mitei'ior spiracle. 



6. bulb of stifiinutic trunk. 

 b.h. branching liair of posterior 

 spiracle. 

 c.p.h. ceplialo-pliarynReal band. 

 c.p.a. cepbalo-pbaryngeal sclerites. 



c.r. cephalic chitinous ridges. 

 c.r.t. "teeth" on cephalic chitinous 



ridges. 

 c.s.o. cephalic sense organ. 

 d.m. dilator muscles of pharynx. 

 tl.v. dorsal vessel. 

 y. fissures in stem of anterior 

 spiracle of BaUoptera. 

 f.c. felted chamber of spiracle. 

 hy. hypoderniis. 

 i.s. intermediate sclerite. 

 i.s.p. peduncle of cephalic imaginal sac. 

 I. labium. 

 l.h. lateral traciieal branch. 

 l.f. lateral flap of cepluilo-pharyngeal 



band. 

 l.p. Labial palp sense organ. 

 l.t. dorso-lateral tracheal trunk. 

 in, mandiiilo. 

 m.n. median nerve. 

 m.nn. muscle nucleus. 

 m.p. maxillary palp. 



m.pl. 



m.v.l. 



VIJ- 

 ph. 



p.ii. 



j).o. 



pr. 



p.s. 



p.sp. 



.s.e. 

 s.m. 



s.p. 

 s.pr. 



t.c. 

 t.s.o. 



t'.l. 



v.s. 



v.t. 



u'.r. 



X. 



mediate plate of cephalo-pharyn- 



geal band, 

 median ventral sclerite. 

 proventricular ganglion. 

 j)harynx. 



proventricular nerve, 

 pre-oral .sense organ, 

 proventriculus. 

 pharyngeal sclerite. 

 posterior spiracle, 

 ridge on bulb of stigmatic trunk, 

 spiracular opening, 

 stigmatic scar, 

 sheatliing membrane of anterior 



spiracle, 

 stigmatic plate, 

 suspensory process of Weis- 



mann's ring, 

 transverse coinniiasure. 

 tlnu'acic sense organ, 

 vestigial leg sense organ, 

 vertical suspensor of dorsal 



vessel, 

 vestigial stigmatic trunk. 

 Weismaun's ring, 

 point of junction of salivary dnet 



with pharynx', 

 opening of doi'sal ves^■el into 



supra-CBSophageal sinus. 



' List of Literature. 



(Only those titles are given which are referred to in the text.) 



1. Becker, R. 1910. " Zur Kenntniss der Mundteilo und des Kopfes der Dipteren- 



Larve." Zool. Jalirb. Abt. fiir Anat. u. Out. der Thiere, IJd. xxix. 



2. Carpenter, G. H., and Pollard, F. J. S. 1918. "The Presence of Lateral 



Spiracles in the Larva of Hypoderma." Koy. Jr. Acad. Proc. vol. xxxiv. 

 ser. B. No. 4. 



3. Hennegut, L. F. 1901. Les Insectes. Paris. 



4. Hewitt, C. G. 1914. The House-Fly. Cambridge. 



