134 GENUS SIEEX. 



The female lays 100 eggs according to Hartig. 

 The duration of the larval life appears to vary. They 

 may become full-fed in seven or eight weeks, but 

 others appear to take a much longer period ; and the 

 period in which they may remain in the larval stage, 

 even after they are apparently full-fed, is uncertain. 

 The perfect insects make a humming noise when 

 flying. 



It is difficult to say how many species may be really 

 indigenous in Britain, possibly not more than two, 

 gigas and juvencus ; and even with these (and especially 

 the former) very few of the specimens taken alive are 

 of native origin, the vast majority having been intro- 

 duced with foreign timber. They often are found near 

 wood-yards, railway stations, and in coal-pits. As 

 nearly all the European species have been found in 

 Britain, I give a synopsis of them. In addition to 

 these, Sirex cyaneus, Fab., = nigricornis, Newman, = 

 duplex, Shuckard; S. albicornis, Fab., 8. flavicornis, 

 F. (of which 8. bizonatus, Ste., is a var.), and 8. 

 Stephensii, Kirby,=ma#?ms, Ste., all natives of America, 

 have been found occasionally. 



Synopsis of European Species. 



1 (4) Antennae short, thick, somewhat fusiform ; twelve- to six- 



teen-jointed ; posterior tibiae and base of tarsi flattened. 

 Wings with three cubital cellules. = Tremex, Jur. 



2 (3) Dull black ; abdomen yellowish, more or less black ; wings 



yellowish. Antennae fuscous, testaceous at base. 



Fuscicornis, F. 



3 (2) Blue ; abdomen with white spots ; apex of antennae white ; 



wings smoky. Magnus, F. 



4 (1) Antennae longish, filiform or setaceous, with more than 



eighteen joints. Wings with four cubital cellules. 



= Sirex. 



5 (10) Body for the greater part blue. 



6 (7) Posterior tibiae with one spur. Ovipositor nearly as long as 



the body, or at least as long as the abdomen ; sides of 

 pronotum testaceous ; the vertex marked with white. 



Spectrum, Fab. 



7 (6) Posterior tibiae with two spurs. Ovipositor not much longer 



than, if so long as, half the length of abdomen ; sides of 

 prothorax not testaceous. No white marks on vertex. 



8 (9) Patellae on joints 2 4 of hind tarsi distinct. Antennas pale 



at the base. Juvencvs. 



