TENTHREDINID^. 215 



question whether the increase in size of the eggs of the Saw- 

 fly is not rather due to the same cause. 



-The punctures in the plant often lead, in some genera, to tlie 

 production of galls, in whicli the larvae live, thus showing 

 tlie near relationsliip of this family to the gall-flies (Cynipidsc), 



The larvae strongly resemble caterpillars, but there are six 

 to eight pairs of abdominal legs, whereas the caterpillar has 

 but Ave pairs. Many species curl the hind body up spirally 

 when f^edhig or at rest. They are usuallj^ green, with lines 

 and markings of various colors. They usually moult four 

 times, the last change being the most marked. Most of the 

 larvae secrete silk and spin a tough cocoon, in which they hiber- 

 nate in the larva, and often in the pupa state. The pupa has 

 free limbs, as in the other families. The eggs are usuall}' de- 

 posited in the leaves of plants, but in a few cases, according 

 to Norton, iu slender or hollow stems. While some are slug- 

 shaped, like the Pear-slug, others like Lyda inanUa, mentioned 

 by Westwood, live on rose bushes, and construct a "portable 

 case, formed of bits of rose-leaves arranged in a spiral coil ; " 

 and other species are leaf-rollers, like the Tortricids. The 

 larva of CejjJius does injury to gi'ain, in Euiope, by boring 

 within the stems of wheat. A remarkable instance of the care 

 of the saw-fl}^ for her young, is recorded by Mr. R. II. Lewis, 

 who observed in Australia, the female of Perga Lewisii deposit 

 its eggs in a slit next the midribs of an Eucalyptus leaf. They 

 were placed transversely in a double series. "On this leaf 

 the mother sits till the exclusion of the larA^ae ; and as soon as 

 these are hatched, the parent follows them, sitting with out- 

 stretched legs over her brood, protecting them from the attacks 

 of parasites and other enemies Avith admirable perseverance." 

 (Westwood.) 



The species are mostly limited to the temperate zone, but 

 few being found in the tropics. The perfect insects mostly 

 occur in the early summer, and are found on the leaves of the 

 trees they infest, or feeding on flowers, especially those of 

 the umbelliferous plants. 



The genus Cimbex contains oin* largest species, the antennae 

 ending in a knob. C. Americana Leach is widely distributed, 

 and variLvj greatly in color. The large whitish larva, with a 



