8o OUR HOUSEHOLD INSECTS 



The basal segment of germanica carries three large 

 and distinct black spots in its yellow band, the centre 

 of which is diamond-shaped ; vulyaris, instead of this 

 diamond, has simply an angular indentation. But these 

 two species are sometimes very difficult to separate, 

 especially the workers, since the markings on the abdo- 

 men vary a good deal, and even those on the face are 

 not quite constant. Sylvestris is sufficiently separated 

 from the rest by its single clypeal spot. 



We still need a reliable means of separating norvegica 

 from rufa. This is to be found in the compound eyes, 

 which, in the latter species, are continued to the base 

 of the jaws, but in the former do not extend so far. 

 Sylvestris agrees with norvegica in this respect. We 

 may add to these distinctions, that while the ground - 

 wasps have a yellow stripe in the scape of the antennae 

 only in the males, the tree wasps have it in all sexes. 

 As if, however, to prevent the use of this as a reliable 

 diagnostic character, the female of rufa sometimes takes 

 on a yellow stripe. The coronet-shaped spot, too, varies 

 in the different species, but not in such a way as to be 

 rendered easily intelligible in words; and the above 

 distinctions will, in most cases, suffice for the determina- 

 tion of the species. 



Few people seem to be familiar with the hornet, 

 except by name; and two totally different insects are 

 commonly mistaken for it. One of these is a large 

 Dipterous, or two-winged insect, the largest fly we 

 have in this country. It is a robust, black and yellow 

 creature called Asilus crabroniformis, the specific name, 

 which means "hornet-like," being given in allusion to 

 the above error, crabro being the Latin name for a 

 hornet. It is a common insect in the summer-time in 

 many places (not indoors, however), and dashes about 



