1922.] , 173 



22 (21) Second abdominal segment at the base generally, the third always 



with evident piuictiiration, which is often dense, though very fine ; 

 propodeum on its posterior face generally with evident raised 

 wrinkles, and altogether less smooth than that of the preceding. 



23 (24) Mesonotum somewhat coarsely and deeply punctured for the small 



size of the insect, the punctures hardly remote ; the propodeum 

 with the anterior area always very coarsely rugose, and on each side 

 adjoining- the area •(?. e., between this and the dorso-lateral angles) 

 equally coarsely rugose dimidiatus v. Hag. 



24 (23) Mesonotum finely punctured, the punctures often shallow and some- 



times very remote ; propodeum very variable in sculpture 



.... varieyatus and afpnis v. Hag. 



The males of the species of Sj)Jiecodes can nearl}^ always be 

 separated without exposure of the genital armature ; but in the case of 

 some very aberrant example it is safer to do this, though the natural 

 form of the in.sect may be somewhat altered in the process. S. <//y«i- 

 d i at us and f/J^n is i\re perhaps not ahva^'s to be determined witli certainty 

 without examination of the armature, though I have not now a sufficient 

 number of the former to be sure on this point, not knowing the extent 

 of its variation. I am unaljle to find any good characters to separate 

 the 5 of va)-ie(/afus from that of affinis. both species being excessively 

 variable in size ami points of sculpture. In a recent work Dr. lieinhold 

 MeA'er distinguishes them thus : — 



Head, seen from above, broad varieyatus. 



Head, seen from above, narrow affinis. 



In my paper * on the Kirby collection I suggested that *S'. scabri- 

 collis might be parasitic on Halictus 4-ciiictus. TJie Halictus meant 

 was the 4t-cinctus of Kirby and British authors, not the species so called 

 on the Continent. 



In conclusion, it should be stated that our British species may be 

 looked ujDon as forming three very distinct groiips, which, no doubt, will 

 at some future time be considered as genera, or will be still further 

 divided up in all probability. To some extent these groups probably 

 correspond to the genera that Cockerell and Robertson have already 

 proposed for the American species. 



The group of c/ibhus contains five of our largest species, remarkable 

 generalh' for the long antennae of the 6 and especially for the 2:)eculiar 

 sculpture of these organs, as compared with the other grovii^s. The 

 females are generally easily distinguished b}^ the greater number of alar 

 hooks, and in most of our species by the peculiarly narrow pygidial area. 



Ent. Mo. JMag. 1917, \t. 48, 



