34 [February, 



really indigenous. Boring as they do in solid timber, their larvae get 

 conveyed about with it from place to place, and may reach us from 

 other countries, or even from other continents. 1 have myself met 

 with <b'. gigas in Upper Egypt, where it is certainly not indigenous. 

 No doubt it simply arrived by boat and rail in European timber. 



Two species are pretty often found in this country, gigas, L., and 

 noctilio, ¥. (= melanocerus, Thorns.) . These are not likely to be con- 

 fused, at least in the ? $ , gigas having a hornet-like coloration, its 

 dull finely rugulose abdomen being fuscous at the base and tawny- 

 yellow at the apex, while noctilio $ has the basal and apical abdominal 

 segments shining blue-black, and the intermediate ones obscurely 

 violaceous. Also in gigas $ the dorsal apex is rounded at the sides and 

 produced centrally into a long " mucro " or spike which is dilated in 

 its middle, while in noctilio the apes is nearly an equilateral triangle, 

 with jagged edges and a comparatively short and simple pointed ex- 

 tremity. The males are not so strikingly dissimilar, but gigas is 

 usually larger, has yellow anteuuse, and a dull abdomen. In noctilio 

 the antennae are black, the abdomen (which in this sex is not coloured 

 as in the female, but yellow with a black apex), has a shiny look, 

 which at once distinguishes it »from gigas, and (a character which also 

 separates the females) the 3rd joint of the antennae is distinctly 

 longer than the 4th. In gigas it is, if anything, shorter. 



Specimens of noctilio, h\, are, i believe, constantly recorded in 

 this country under the namajuvencus, F., and 1 have probably named 

 them so for correspondents myself. But if the true juvencus occurs 

 at all in Britain, it must be very rare, i have it from Switzerland, 

 but have never seen a British specimen which J can confidently refer 

 to it. TvMQ juvencus ought to have the antennae widely yellow at the 

 base, the vertex finely punctured and not deeply sulcate ; its $ should 

 have all the legs red up to the coxae, the saw-sheath (viewed laterally) 

 slender and scarcely rugose ; in the ^ the 8th dorsal segment should 

 be blue only at the sides. Thomson adds that in both sexes the tarsal 

 joints 2—4 aa\e in juvencus "patellas completas," and in the other 

 species " patellas minimas apicales." This he regards as the most 

 important character for separating the two insects, but I am bound 

 to say that i have found it a very difficult one to realize, though I 

 have tried hard to see it in my own specimens. With the two species 

 actually side by side one does see a certain difference, but I should be 

 sorry to have to determine an isolated specimen by means of it. 



(3) Oryssus ahietinus. Scop., is a rather small insect with bright 

 red abdomen. Stephens says that Dr. Leach took one in 1817 at 



