TENTHREDINID.E, OR SAW-FLIES. SIRICID^E. 



169 



agile in the hot sunshine. They come forth for the most part in 

 the spring, having passed the winter in the pupa state ; and they 

 usually obtain their chief supply of food from the pollen or honey 

 of flowers, especially those of the Umbelliferous tribe ; some of 

 them, however, attack and devour living insects which frequent 

 the same plants. The ravages of these insects are restrained 

 by the destruction of vast multitudes of their larvae, through the 

 agency of the Entomophagous or parasitic section of this group ; 

 thus the Lophyrus pi?ii, a Saw-fly which infests the Pine, is it- 

 self subject to the attacks of at least twenty parasites, of which 

 fifteen are Ichneumonidse. 



754. The SIRICID^E bear a strong general resemblance to the 

 preceding group, both in structure and habits ; but they have a 

 stronger ovipositor, agreeing in structure with that of the Ento- 

 mophagous section, which enables them to pierce not merely the 

 soft substance of leaves or young shoots, but hard timber. The 

 larvae produced from the eggs thus deposited, usually reside in 

 the interior of trees, which they perforate in various directions ; 

 often causing great destruction in the Pine forests, of which the 

 largest species are inhabitants. When full grown, they form 

 a slender silkon cocoon, mixed with chips of wood, at the 



^. %s ^ extremity of the 



>v s burrow ; and here 



they undergo their 

 final transformation. 

 ^^ The perfect Insects 

 are among the largest 

 of the Order ; they 

 are remarkable for 

 the very cylindrical 

 form of their bodies, 

 and for the hum- 

 ming sound which 

 they make when on 



PIG.485.-SIKEX GIGAS. the wing> 



755. SECTION II. In the section of TEREBRANTIA ENTOMO- 

 PHAGA, the first family, that of CYNIPID.E, or Gall-flies, rather 



