Benham. — Aquatic Larva of the Fly Bphydra. 309 



gives a poor figure (vol. ii., p. 569, group 132, fig. 11) which 

 shows the bifurcated tail, following ten claw-bearing segments. 

 He states (p. 574), " Many species of Ephydra frequent salt 

 marshy situations. The larva is cylindrical, without feet, and 

 the terminal segment of the body very long, and terminated by 

 a long fork, the prongs of which support spiracles at the tip ; 

 the puparium scarcely differs from the larva." Packard, on 

 p. 414, also represents, in a slightly more detailed figure, the 

 " puparium " of another species. I find no reference to the 

 genus in MialPs interesting book, nor in the Cambridge Natural 

 History. 



Description of the Puparium. 



Amongst the dark-brown puparia I find one grey larva, which 

 differs in a few points from the puparia, to which I paid more 

 special attention ; and since the larva, by hardening of the stem, 

 becomes the puparium, the description of the latter will serve, 

 with slight modifications, for the former. The puparium is a 

 dark-brown hard-skinned object, measuring 9 mm. in total length, 

 with a greatest diameter of 2 mm. It is cylindrical, bluntly 

 pointed anteriorly, and produced into a narrow cylindrical tail 

 occupying about one-third of the total length — viz., 3-5 mm. 

 This terminates in a pair of short, narrow tubes, paler than the 

 body, but tipped with dark pigment ; each branch or tube is 

 1 mm. in length, and bears a spiracle at its apex. The entire 

 surface — except these terminal branches — -is covered with closely 

 set blackish spines (as in Eristalis), groups of which at certain 

 segments become larger and claw-like. 



The body consists of a small " head,"* carrying a mouth, 

 followed by ten distinctly marked segments, the last bearing 

 the anus, behind which is the long tail. 



There are no definite feet on this puparium, but on the ventral 

 face of each of the eight segments 3 to 10 are paired groups of 

 black claw-like spines, those on the last segment being carried 

 on a prominent median papilla. In the majority of the specimens 

 the ventral surface of the 9th segment is sunk below the general 

 level, and, the body being abruptly curved ventralwards in this 

 region, the claws of segments 8 and 10 are brought close together, 

 and even in contact in some specimens, thus giving rise to clasp- 

 ing-organ. 



Westwood's figure shows nothing of this kind, all the segments 

 being represented alike, and he places claws on all ten segments. 

 Packard's figure, however, shows a slight prominence behind 

 the 7th, and another larger one on the 10th. These, however, 

 are wide apart, and do not suggest a clasping-organ. 



* Possibly the true head is retracted. 



