1873.] 145 [Packard. 



ridge on this neck is much sharper and more pronounced than in 

 C. vomitoria, and the impressed lines on the sides extend forwards 

 to the suture between the penultimate and terminal segments of the 

 body, the lines curving outwards anteriorly. There is a well-marked 

 pointed short ventral ridge behind the rudiments of the ventral prop- 

 legs. This ridge is obscurely marked in the puparium of C. vomi- 

 toria, except that the prothoracic spiracles are much less prominent, 

 not projecting beyond the head, their extremities being just parallel 

 with the end of the rudimentary mouth-parts. The edge of the 

 spiracle is rugose, but I have been unable to distinguish any signs 

 of lobules. The lines of pointed granulations are arranged much as 

 in C. vomitoria. Length .50 inch. 



The pupa. (Fig. 11.) The pupa of M. domestica may at once be 

 known by its broad spatulate labium or tongue, and the curved, al- 

 most elbowed maxillary palpi. The antennas (Fig. 1 1 d) are dis- 

 tinctly three-jointed, with a large, stout bristle. Fig. 11a shows one 

 of the legs with the trochanter hanging to it; Fig. 116 the wing, sur- 

 rounded by its membrane ; and Fig. lie the optic lobes, and their 

 connection with the unorganized cornea and facets of the eyes; the 

 outer surface of the eye being covered with fat cells, destined to form 

 pigment cells, which finally turn reddish. 



The figures 12, 12 a, 12&, show the corresponding stage in the 

 pupa of Stomoxys calcitrans; here can be seen the generic characters 

 which separate this fly from the House Fly, i.e., the elongated beak, 

 the smaller, narrower, more pointed head. The mouth-parts with 

 the long maxillse (nix) and mandibles (m), and the straight maxillary 

 palpi, are shown in the enlarged view (Fig. 12c). 



On removing the puparium we were able to obtain a portion of the 

 semipupaof Stomoxys (Figs. 13, 13 a) i.e., the thorax, the head adher- 

 ing to the pupa-case, and only the basal segment of the abdomen 

 being brought to view; enough, however, to show that they were 

 nearly of the form of those of the larvse. This stage compares almost 

 exactly with that of Calliphora vomitoria, as figured by Weismann, 

 Tab. xii., Figs. 38, 39, 40. This stage is intermediate between 

 the larval and pupal, and may be properly termed the semipupa. 1 



1 Professor von Siebold, in his "Beitrage zur Parthenogenesis der Arthropoden," 

 1871, p. 35, calls this stage pseudo-nymph. As this state is necessarily universal in 

 all metabolous insects, it seems incorrect to regard it as a false or unusual state, and 

 we therefore may be pardoned for retaining the name first proposed by us in 1866. 

 (Proc. Bost. Soc. N. H., x, 279.) 



PROCEEDINGS B. S. N. H. — VOL. XVI. 10 FEBRUARY,. 1874. 



