191S.] 171 



of A. nana owing to the difference in the antennae of the (J , and tlie 

 sculptured apices of the abdominal segments in the ? . The antennae 

 in the latter sex often have nearly the whole flagellum brightly ferru- 

 ginous beneath, and also sometimes they are less conspicuously so in 

 the (^ . I have seen fewer examples of this than of any of the other 

 species. I took ^J (^ on JJinhelliferfe in August, about 14 years ago, 

 near Mildenhall, and the ? in September, 1886, at Dawlish. Colonel 

 Nurse has sent me for examination 3 ^ and 3 ? from Eastbourne 

 (August), and 1 ^ (July), and 1 ? (August) from Timworth, Suffolk, 

 and 1 have examined a few other specimens. 



Park Hill House, Paignton : 

 June Ist, 1913. 



SOME INTERESTING BRITISH INSECTS (V).* 



BT F. W. L. SLADEN, F.E.S., E. S. BAGNALL, F.L.S., AND 

 J. E. COLLIN, F.E.S. 



The two plates accompanying this ai-ticle illustrate one species of 

 Hymenopfera, two Thysanoptera, one Proturon, and seven Diptera. 



Plate II. 



Figs. 1, 2. — Psithyrus distinctus, Yerez (1 c? , 2 ?, x 1^). This 

 is an interesting British bumble-bee because, so far as the writer knows, 

 no description of it has been published in England, except that given 

 recently in " The Humble-bee. "t The insect was, however, well known to 

 Edward Saunders in his later years, who regarded it as a variety of 

 P. vestalis to w^hich, indeed, it is closely related. 



The males of the two forms differ in the quality and colour of 

 their coats : in distinctus the hairs are less equal in length, and the 

 yellow is paler and more extensive. They may also be easily separated 

 by the structure of the antennae : the 5th joint in vestalis is about as 

 long as, but in distinctus much shorter than, the 3rd and the 4th joints 

 taken together ; in vestalis the flagellum is about 6 mm. long, in 

 distinctus it is only about 5 mm. long. 



The female of distinctus is somewhat smaller than normal- sized 

 females of vestalis, and has the yellow band on the anterior part of the 

 thorax and the yellow on the sides of the 3rd abdominal segment paler 



* cf. (I) Eiit. Mo. Mag. XLV, pp. 19t), 197, pi. Ill (1909) ; (II) XLVI, pp. 1-3, pi. I (1910); (Hf) 



XLVII, pp. 203-200, pi. Ill (1911). 

 t "Tlie Humble-bee," by F. W. L. Sladen, 1912 (London, Maemillan & Co., Ltd.), pages 210-113. 



P 2 



