506 



HYMENOPTERA 



escape ; it leaves the bark, however, untouched, and is thus pro- 

 tected in its retreat. A delicate transparent cocoon is then spun 

 in which the larva passes the winter, changing to a pupa in the 

 following March, and emerging as a perfect Insect about six 

 weeks thereafter. 



Somewhat less than 100 species of this family are at present 

 known ; the great majority are found in the Mediterranean 

 region, but there are several in North America. As a single species 

 is known from Mexico and another from Japan, it is probable 

 that the family may prove to have a wider geographical exten- 

 sion than at present appears to be the case. 



Fam. II. Oryssidae. 



The median plate behind the metanotum entire, not divided in tlie 

 middle; antennae inserted 'below the eyes immediately above 

 the mandibles, under a sharp edge. 



This family consists of the genus Oryssus, and includes only 

 about twenty species, but is nevertheless very widely distributed 



over the world. They are very 

 rare Insects, and little is known 

 as to their habits ; one species, 

 0. abietinus, was formerly found 

 in England. Should any one 

 be so fortunate as to meet with 

 it, he can scarcely fail to re- 

 cognise it on noticing the 

 peculiar situation of the base 

 of the antennae. In this re- 

 spect the Chrysididae somewhat 

 resemble Oryssus, but in that 

 group of Hymenoptera the hind 

 body or abdomen is remarkably 

 mobile, so that the Insects can 

 coil themselves up by bending 

 North America. a t this joint ; whereas in Oryssus 



A, The female Insect ; B, head seen the hind body is VCiy closely 

 from the front. . n ., , ,-, ,-, 



amalgamated with the thorax 



more so, in fact, than in any other Hymenopterous Insect and 

 has no power of independent movement. 



say. 



