174 



FOREST ENTOMOLOGY. 



It should be noted that, from a systematic point of view, the species 

 attached to hawthorn has hitherto been known as Tricliiosoma lucorum, 

 but modern classification associates the latter name with another 

 species which is attached to birch-trees. 



This species is in every way an interesting forest insect, but in 

 no sense whatever can it be termed an injurious insect. The large 



and somewhat pretty larva may often be 

 found on thorn hedges, when we are quietly 

 searching for anything of an arboreal 

 interest. 



The larva (fig. 162) when young has 

 a greyish - white appearance, largely due 

 to a powdery covering, which appears 

 dusted over the body. As it gets older 

 the colour is a blend of green with 

 light yellow, with a yellowish face 

 and black eyes. It may be looked 

 for in July. It is not a voracious 

 feeder. 



The pupa (fig. 161) is a hard brown 

 cocoon, | inch to 1 inch long, and inch 

 to J} an inch in breadth. It opens by a 

 lid for the exit of the perfect insect. It 

 may be looked for during the winter 

 months on thorn hedges, more especi- 

 ally towards the bottom of the hedge. 



The perfect insect may be seen hovering 

 in thorn hedges in March and April. It 

 may be mistaken by the uninitiated for 

 a bee. It is a brownish colour, head, 

 thorax, and abdomen hairy. Antennae dark - brown. Legs a light- 

 brown. The wings are clear. Length 6-10 lines. 



The genus Cimbex is very closely allied to Tricliiosoma, but in a 

 general way the former may be distinguished from the latter as being 

 less hairy. For practical purposes we may group the two genera 

 together ; and Judeich and .Nitsche, though giving different generic 

 -characters, adopt this method for general description. 



Fig. 161. Pupa of Tricliiosoma 

 on hawthorn after escape of fly. 

 (From drawing by P. J. Brown.) 



