314 Mr. T. D. A. Cockerell — Descriptions and 



E. Turner examined 14 female specimens in his collection, 

 and all bad 13-jointed antennse and wholly lacked a ventral 

 scopa. It is therefoi'e certain that this is a normal condition, 

 and must represent an early stage in the evolution of a 

 parasitic series, like those of Caelioxys and Stelis. From the 

 standpoint of genetics, it is an extraordinaiy case, since the 

 female seems to have dropped her secondary sexual characters 

 and thereby assumed those of the male, which were present 

 in her gametic constitution. It is noteworthy that the sting, 

 a modified primary character, is retained. It appears that 

 in Megachile the female is heterozygous for the secondary 

 sexual characters, with the female characters dominant. 



Thus a new generic type has been produced by the simple 

 dropping out of one set of characters. It may be objected 

 that the insect is still essentially a Megachile^ and this is in- 

 deed true as regards its major characters, but according to 

 any logical system of classification it must go in a distinct 

 generic group, as otherwise our current definition of Mega- 

 chile, applicable to hundreds of species all over the world, 

 breaks down. 



Mr. Turner sends me the male of A. detersa, taken at the 

 same tree as the female^ and having the same general 

 characters. 



Male. — Length about 8 mm. Eyes green ; face with 

 abundant pale yellow hair; third antennal joint (as 

 Mr. Turner noted) oblique at end as in the female; lower 

 part of cheeks with very abundant snow-w liite hair ; anterior 

 coxae with short flat spines ; anterior tarsi reddish, the first 

 three joints oval, flattened, especially the first, so that the 

 posterior margin of the tarsus is strongly creuate, the tarsus 

 also Avith a strong fringe of white hair behind ; middle and 

 hind tarsi also somewhat thickened, middle tarsi with a very 

 long fringe of white hair behind ; hind tibia swollen ; vertex 

 and thorax above with a good deal of black hair ; abdomen 

 short, with narrow hair-bands, the aj^ex strongly retracted ; 

 dorsal surface of sixth segment densely covered with cream- 

 coloured hair, margin of segment little projecting, with a 

 broad shallow median depression ; no ventral teeth or spines ; 

 claws bifid at end. The claws are also bifid at end in the 

 female, with no basal tooth. 



Heriades sauteri, sp. n. 



? . — Length about 6^ mm. 



Black, superficially looking exactly like the European 

 H. trn)icorum (L.), to which it is closely allied, differing as 



