152 



KNO^VLEDGE 



[March 1, 1886. 



edge to the centre of the lower, and more or less dilated 

 near the lower extremity into two lateral projections ; in 

 the males and females, the mark usually does not quite 

 reach the l(]wer margin of the clypeus, but terminates at 

 these projections, and it thus acquires something of the 

 a[)pearance of a cheese-cutter with a long and stout 

 handle. It has also been likened, with less justice, to an 

 anchor, and hence both these species are sometimes called 

 anchor-faced wasps. Norcegica also carries the anchor- 

 mark on its clypeus; so that there are three species 

 adorned in this '^^■ay, two ground-wasps and one arboreal 

 species. 



^^ 



Fig. 1. — Coronet-spots and clypei of wasps. A, V. ruIr/arig,{emB\e; 

 B, rulgnris, worker; C, (jermanica, worker; D, germmiica 

 female ; E, si/livstris, worker. ' 



Germanira, on the other hand, carries, in the workers 

 a central black stripe, stretching only part of the way 

 down the clypeus, and often more or less imperfect, and 

 two black dots placed triangularly with the free end of 

 the stripe. In the males and females, there are usually 

 simply three black dots placed triangularly, without a 

 black stripe at all. Lastly, sijleedris has only a single 

 black dot in the centre of the clypeus, or, in the females, 

 often no black markings at all. 



Turning now to the basal segment of the abdomen, we 

 find that rufa has some rusty stains around the black 

 s|iots there, in addition to the yellow band which occupies 

 tlie greater part of the segment, and the .same rusty hue 

 often occurs on other segments as well; it is from this 

 peculiarity that the .species derives its name (rM/a = red). 

 Bat -it would not ba .safe to conclude that any anchor- 

 faced, red spotted wasp is rufa, since nnrvegira is usually 

 similarly coloured; the red "colour, however, will .serve 

 to distinguish rnfa from rulgarU, both of wliich, it will 

 hi' remembered, ar,^ anchor-faced. 



The basal segment of ijermanica carries three large and 

 distinct black spots in its yellow band, the centre one of 

 which is diamond-shaped ; vnhiarU, instead of this 

 dr.imond, has simply an angular indentation. But these 

 two species are sometimes very difficult to separ.ite, 

 especially the workers?, since the markings on the abdomen 

 v.iry a good deal, and even those on the face are not quite 

 constant. 8ijh-edrU is sufficiently separated from the 

 r.'st liy its single clypeal spot. 



We still need a reliable means of separating norvcgica 

 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. Siilves- 

 tris agrees with noroegica in this respect. We may add 

 to these distinction.s, that while the ground-wasps have a 

 yellow stripe on the scape of the antennas only in the 

 males, the tree-wasps have it in all sexes. As if, how- 

 ever, 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 

 diffei-ent 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 determination of the 

 species. 



Few people seem to be familiar with the hornet, except 

 by name, and two totally diiferent insects are commonly 

 mistaken for it. One of the.se is a large Dipterous, or 

 two-winged, insect, the largest flij we have in this country. 

 It is a robust, black and yellow creature, called Asilns 

 crahroiiiformi^, the siJecific name, which means " hornet- 

 like," being given in allusion to the above error, crahro 

 being the Latin name for a hornet. It is a common in- 

 sect in the summer time in many places (not indoors, 

 however), and dashes about with bold and vigorous flight 

 and great buzzing, and with so martial an air that it is 

 not surprising that those who do not know its real 

 nature should be intimidated by it. It is, however, a 

 perfectly harmless creature. 



The other insect sometimes mistaken for a hornet 

 comes a little nearer the mark, for it is hymenopterous ; 

 but still it does not belong to that section of the order 

 which contains the wasps and other stinging insects. It 

 is closely related to the group of saw-flies, and is one of 

 the largest hymenopterous insects we possess. It is a 

 yellow and lilack powerfuUy-tiying creature called Sirex 

 glgas (the specific name is given in allusion to its gigatitic 

 size), and the female, which is the sex most often seen, 

 possesses a hmg and stout ovipositor, which looks 

 dangerous enou.gh, though it is simply a kind of auger, 

 and not a poisonous weapon at all, so that the insect, 

 though so formidable in appearance, is in reality harm- 

 less. This great ovipositor has acqiiii'ed for its possesstir 

 the name of " Horn-tail." 



Both the .above insects are yellow and lilarl; and, as we 

 have already seen, the latter colour forms no part of the 

 ornamentation of a hornet ; moreover, when one comes 

 to look at them closely, they are at once seen to be 

 altogether unlike wasps, though, of course, when they 

 are on the wing, and dashing rapidly about, it is not so 

 easy to see this. Now the hornet, the scientific name 

 for which is J'esjja crabo — i.e., reversing the order of 

 the words, the "hornet wasp," — is in shape exactly like 

 an overgrown wasp ; so thr.t its form must be familiar to 

 every one. We have only to imagine tlie yellow oi the 

 wasp's body to be deepened in tone, the black to be re- 

 placed by b/own, and the whole insect to be considerably 

 magnified, and the wasp becomes a liornet. If this be 

 borne in mind, there .should be no difficulty whatever in 

 recognisiu')- a hornet, for there is no other British insect 

 to which the description will apply. Since the Sire.v is 

 not unfrequently found in houses, as well as the hornet, 

 it is all the more necessary to be able to distinguish the 

 harmless insect from the dangerous one. The hornet's 

 wings, like those of a wasp, are covered with a profusion 

 of tiny hairs, which, however, are so small as to be quite 

 invisible without the aid of a microscope. 



The hornet constructs its nest of a material prepared 

 similarly to that used by the rest of the genus, but it is 



