THE MAXILLA PALPI. <5 



to near the top of the outer lobe ; this being the case, 

 too, with Tenthredo, only it is longer. Generally the 

 parts are more or less membranous, especially at the 

 apex. 



The maxillary palpi vary only in the relative size 

 and length of the different joints, and in number (at 

 least, so far as European species are concerned) they 

 are uniform, namely, six. In Fenusa there is indeed 

 a short intermediate joint at the apex of the third, 

 according to Hartig, but it is doubtful if it can be 

 regarded as a distinct joint, nor does it exist in all the 

 species. Curtis,* too, mentions a species having only 

 five in the maxillary and three in the labial palpi ; but I 

 have not been able to verify this observation, as he does 

 not mention the species, further than saying that it is 

 allied to Selandria. 



The basal joints are horny; the apical are more 

 membranous and lighter coloured, while they may be 

 provided with short hairs. The basal joint is the 

 smallest, the second somewhat larger, and the third is 

 one of the longest. The fourth, again, is often very 

 small Cimbex, Cladius and not unfrequently the 

 joints, from the second, may be pretty much of the 

 same length Dolerus, Athalia, Tenthredo. 



The labium (PL X, fig. 2) is deeply cleft into three 

 nearly equal lobes, which are rounded at the apex and 

 generally of the same size and form. The middle lobe, 

 however, may be larger than the others and truncated 

 at the top. Tenthredo scalaris has a little conical 

 point on the centre of the middle lobe. Some forms 

 have the parts widely separated and well marked, but 

 with Hylotoma, Tenthredina, &c., they are closely 

 pressed together. 



The labial palpi have usually four joints. With 

 Cimbex the third joint is thickened and bulged out, and 

 the fourth knob-like at its outer edge. With other 

 species (Emphytus, &c.) the third is smallest, while 

 with Hylotoma they increase in size from the base. 



* B. R, 764. 



