COMPLEMENTAL MALE. 237 



adheres to the thorax, when the latter is dissected out of 

 the general integuments ; in this condition, I twice clearly 

 made out that it was single : in one other specimen, how- 

 ever, there appeared to be two small vesiculae seminales. 

 By using a condenser and very brilliant light, the outline 

 of the vesicula seminalis could sometimes be distin- 

 guished before dissection, at the bottom of the sack-formed 

 animal ; and such was the case in the specimen drawn 

 in fig. 9. 



Although I have dissected, at least, thirty specimens, 

 taken at different times of the year, and from different 

 localities, and when many of the specimens were mature 

 and ready for the impregnation of ova, as clearly shown 

 by the presence of innumerable spermatozoa, I have never 

 seen even a trace of an ovum or ovaria. 



Antennce and Attachment. — The prehensile antennas 

 (PL V, fig. 10), are seated a little above the very base 

 of the sack-like animal ; and this might have been expected 

 from the antennas in the larva, being seated on the ven- 

 tral surface, not at the very extremity of the head. By a 

 very strong light, they can sometimes just be seen whilst 

 the parasite is attached to the hermaphrodite (the scutum 

 of the latter having been cleaned on the under side), and 

 are thus represented in fig. 9. They are formed of thicker 

 membrane than the general integument of the body : the 

 second segment, or disc, is pointed and hoof-like ; when 

 seen in profile (fig. 11), the upper convex surface has a 

 uniform slope with the upper surface of the basal seg- 

 ment ; it is furnished with a single backward pointing 

 spine, attached, I believe, on the under side, nearly oppo- 

 site the articulation of the ultimate segment : at the apex, 

 there are some excessively minute hairs or down. The 

 ultimate segment projects rectangularly outwards as usual, 

 and has on its inner side, rather beneath the middle, 

 a conspicuous notch (fig. 12), which bears two or three 

 long, non-plumose spines ; on the summit there are three 

 or four rather shorter spines. On the outside of the great 

 basal segment there is a single spine curving backwards. 



