LIFE-HISTORIES OF SAWFLIES. 33 



small ; of course this disproportion is, in the first place, to 

 be ascribed to the usual causes limiting, in the case of all animals, 

 the number of individuals arriving at maturity, but also, in 

 the second place, to the long continuance of cold in the spring of 

 1874, which destroyed so many insects. The question now 

 arises whether I am right in correlating the imagos I had captured 

 with the larvae I had observed : without doubt to accept such 

 a conclusion would in manj^ cases be taking too much for granted ; 

 but when we consider that Circcea lutetiana is a very local plant, 

 and that it is used as food by but few insects, — that among these 

 only a single sawfly larva is known, which is the species now 

 under consideratio^i, T. Colon, — moreover that my insects com- 

 pletely agree with the description given by Kaltenbach, who 

 succeeded in rearing this species, — I think it will generally be 

 conceded that I am justified in assuming the specific identity of 

 my larvse with the imagos I captured. Of course from what 

 I have stated above it follows that I had no opportunity of 

 observing the pupa ; this is, however, the less to be regretted, 

 seeing that in general the pupse of sawfiies offer no points of 

 interest. 



The male imago (figs. 9 and 10) is eleven millimetres long, 

 and expands to twenty-one millimetres. The body is cjdindrical 

 and almost equally broad throughout, with the exception of 

 the shoulders, which are somewhat wider, and the head, the 

 breadth of which is caused by the projecting e^'es, between which 

 the forehead is deeply indented ; the posterior margin of the 

 head is angularly truncated, and even appears to be narrowly 

 bordered. 



The head is entirely black, with the exception of the clypeus 

 and the trophi. The clypeus is very deep, roundly emarginate, 

 the upper lip is circular and very projecting; the mandibles are 

 brown at the tip, shading off into black ; the 3rd and 5th joints of 

 the maxillary palpi and the last joint of the labial palpi are black 

 at the tip. The ocelli are black and small, and are placed some- 

 what on an elevation ; the basis of the antennae also projects from 

 the cavity of the face. The antennae are black, and are nine- 

 jointed ; the 2nd joint is inserted obHquely on the 1st ; the three 

 penultimate joints are white, the 6th being black at the base. 



The thorax, rendered dull by the puncturation, is black, with 

 fine grey pubescence ; the tegulae are pale brown, and the cenchri 



F 



