i6 HYMENOPTERA ACULEATA. 



beginning or middle of October there is hardly anything 

 to be found in this country. 



Divisions. 

 The Aculeates can be divided in four large sections by 

 the follow^ing characters : — 



(6) 1. Hairs not plumose or brauched, basal joint of 



the hind tarsi not dilated. 

 Wings, wben at rest, not folded longitudinally. 

 Petiole of the abdomen, with one or more 



scales or nodes, species social . . . Heterogy.va. 

 Petiole sim|jle, species solitary . . . Fussorbs. 

 Wings, when at rest, folded longitudinally . Diploptera. 

 Hairs plumose or branched, at least those of 



the thorax, hind tarsi with the basal joint 



more or less dilated Antiiophila. 



HETEHOGYNA. 



This section is composed of the ants, whose habits and 

 instincts place them very high in the scale of insect life. 

 They nearly all form communities, consisting of (J ? and ? , 

 The c? and $ are almost always winged and the 5 apterous. 

 The abdomen is constricted at the base, its first or its first 

 and second segments either being modified into nodes, or the 

 first segment bearing an upright transverse scale. The 

 anterior tibise have an internal cavity into vphich one of the 

 tracheal vessels enters. This is thought to be an auditory 

 organ. Several $ often inhabit the same nest ; the winged 

 forms swarm out of the nest on a suitable day, generally 

 on one which is very hot and sultry. Impregnation having 

 taken place, the ? sets to work either alone or with such 

 workers as she can attract to found a nest for herself. The 

 larvas depend entirely on the 5 for their food, which consists 

 of honey regurgitated. The form of nest varies very much. 

 Some ants make nests above the ground of fir needles, bits of 

 wood, leaves, &c., as Formica rii/a, &c. Others, as a rule, 

 are subterranean, as F. fusca ; others again, as a rule, select 

 tree trunks as Lasius fidiijinoaus ; others go under stones to 



