isoiM 2GI 



ders, wlio has not only added many species to the list of British 

 Aculeata, but by his works on this group has so greatly advanced our 

 knowledge of the subject. 



Crahro Saundersi is readily separated in the male sex by the fact that the 

 tubercle of the third johit of the aiitennfe bears some long fine hairs, the tubercles 

 being equidistant from one another. The female is easily known by the wide face, 

 the lateral teeth of the apical margin of the clypeus being very remote from the 

 middle ones, and the basal abdominal segment being dull and densely punctured. 

 The ocelli are arranged almost in an equilateral triangle, as in the species known to 

 us as cephalotex, hut for which it would be better to adopt the name cavijrons, Thom. 



The most noticeable characters of the other species, as I observe them, are as 

 follows : — 



Crahro cavifrons. Thorns. (= ceplialotes, Sm., E. Saund. et auct.) $ with the 

 three basal tubercles of the antennae strongly and almost equally developed, the 

 distance between the first and second greater than that between the second and 

 third ; no long hairs on the tubercle of the third joint. Posterior tibiae yellow. 

 ? — lateral teeth of clypeus very near to the middle ones, each being as near to the 

 nearest of the two middle ones as these latter are to one another. Basal abdominal 

 segment not very densely and distinctly punctured. Face less transverse than in 

 C. Saundersi. Ocelli in a neai'ly equilateral triangle. 



Crahro planifrons, Thom. g ^basal two tubercles of the antennae not strongly 

 developed. Posterior tibiae black in the examples examined by me. ^ — each 

 lateral tooth of the margin of clypeus less near to the nearest of the middle ones 

 than these are to one another, the lateral teeth prominent. Basal abdominal segment 

 more shining and less closely punctured than in C. Saundersi. Ocelli in a triangle, 

 wider at the base than that of the preceding species. 



Crahro chrysostomus, St. Farg. ^ — two basal tubercles of antennae very strongly 

 developed, the following ones small ; posterior tibiae yellow. $ — ocelli in a triangle, 

 wide at the base. Basal abdominal segment shining and quite sparsely punctured. 

 Each lateral tooth of clypeus rather more distant from the nearest of the middle 

 ones (which are generally ill-developed and hardly more than angles) than these are 

 from one another. 



Although C. planifrons is not yet known as British, there is hope 

 that it may be found, and perhaps it may even now be included in 

 some collections with C. cavifrons, or with C. chrysostomus, which the 

 female very greatly resembles. Of the above characters I have not 

 found the disposition of the ocelli very easy to appreciate. The dif- 

 ference between C. cavifrons and G. chrysostomus in this respect is 

 manifest, but C. planifrons seems to be somewhat intermediate, and 

 there seems to be some variation in different examples of the same 

 species. Mr. Morice has informed me in his letters that he finds the 

 same difficulty, and that in some cases actual measurements show the 

 difference in the disposition of the ocelli to be very small indeed. 

 Cambridge: Octoher, \'AQ9. 



