Sonic Hypermetamorphic Beetles 17 



Certain authors have called that part which protrudes from 

 the body of the host the cephalo-thorax. Owing to the fact that 

 the eves are located at the posterior end of this structure we 

 must consider it the head, and the constricted neck the thorax. 

 The organs of the head cast aside all doubt as to its identity. 

 Considerable work remains to be done on these structures, and 

 more material is desirable. 



Xenos(?)sp. x 



The triunguloid of this species is brown, robust, very small. 

 Length .158 mm.; width at second abdominal segment .063 mm. 

 Head shorter than broad ; eyes not prominent, consisting of 

 several little blotches of pigment ; antennae very small, not as 

 long as eyes are wide (impossible to magnify high enough to 

 ascertain their character) ; mandibles short, acuminate, about as 

 long as eyes, immediately in front of eyes, not meeting at mid- 

 dle ; other mouth parts too small to recognize distinctly. Legs 

 short, slender, weak, hardly equaling in length the width of the 

 prothorax ; tibiae terminated by long, almost invisible acuminate 

 pad, which is strongly convex on the edge and almost equals in 

 length' the tibiae. Body enlarging gradually to second abdom- 

 inal and then narrowing to the last segment, which is squarely 

 truncate and terminated at each side by a short tubercle, bearing 

 a long, stout, acuminate stylet, which equals about six segments 

 of the abdomen. Dorsum armed with many short stout spines 

 at the apical edge of each segment; venter armed with but few 

 spines on each abdominal segment. 



Twenty-one hundred and fifty-two of these were actually 

 counted as the offspring of one female. They were extracted 

 from the parent's body, in which large numbers of eggs still 

 undeveloped were also found. The parent was found in Ari- 

 el re na solidaginis taken in September at Lincoln. 



Two other females of the same species taken from a specimen 

 of Andre na solidaginis, dated September 18, 1903, appear to be 

 mere sacs full of larvae, many of which have already worked 

 their way to the head. On the other hand two females taken 

 September 30, 1903, on Andrcna solidaginis are full of unde- 



1 See pi. I, fig. 13. 



169 



