524 NATURAL HISTORY OF ARTHROPODS. 



and laying out broad roads leading from it, over which to carry the supply of seeds 

 which it stores up for the winter in subterranean chambers. These nests often occur 

 in cultivated fields, when considerable damage to crops results. The leaf-cutter ant 

 (CEcodoma ferens), however, is a much greater pest to the Texas agriculturist, as it 

 often entirely denudes a fruit-tree of foliage in a single night. Large bodies of 

 workers ascend the tree and occupy themselves exclusively with the work of cutting 

 the leaves, which fall to the ground and are carried off to the formicary by other 

 workers stationed below. 



J. H. COMSTOCK. 



The family CHRYSIDIDJE is a group of small extent, comprising less than five hun- 

 dred described species, of which about one hundred and seventy-five inhabit Europe. 

 The species are of medium size, brilliant colors, and are active and diurnal in habits. 

 They are called " cuckoo-flies " by the English, and " G-oldwespen " by the Germans. 

 The colors are usually brilliantly metallic, and the abdomen is frequently tipped with 

 red. The larger species reach a length of half an inch or more. The head is of 

 moderate size, never exceeding the thorax in width. The antennae are elbowed and 

 thirteen-jointed. The abdomen is large and with but three, four, or (in the male of 

 Cleptes) five visible segments, convex above and flat or concave below, so that it is 

 readily turned under and applied to the ventral surface of the thorax when the insect 

 rolls intself up into a ball for protection. The sheath of the ovipositor is tubular 

 and telescopic, and its segments correspond to the missing segments of the abdomen. 

 The venation of the fore wings closely resembles that of some Proctotrupids (Aphe- 

 lopus and Anteon), and the hind wings are almost veinless. 



In mode of life the Chrysids are either parasites or inquilines, and are usually bred 

 from the nests of wild bees and wasps of the families Apidre, Eumenidaa, Crabronidse, 

 Philanthidae, Nyssonidae, Bembecidffi, or Pompilidae. Some species of Cleptes, how- 

 ever, are true parasites on the saw-fly genus Nematus. Cleptes nitidula has been bred 

 from the imported currant-worm (Nematus grossularice) in Europe, and may be found 

 in this country. It is well proven that while certain species devour the larvae of their 

 hosts, others simply feed upon the stores of food, leaving the original occupants to die 

 of hunger. They are well known to their prospective hosts, and it is said by Walckenaer 

 that the bees of the genus Halictus will congregate together to drive away any indi- 

 vidual of Hedychru.ni lucidulum Avhich has stationed itself at the mouth of their bur- 

 rows to wait for an opportunity to oviposit. 



Certain species may be called secondary inquilines. For instance, Trypoxylon 

 intrudes upon the domiciles of Odynerus, carrying its own store of food with it, and 

 closing the entrance against the return of the female Odynerus. To this conies 

 Chrysis cyanea and lays the egg from which hatches a larva which devours the stores 

 of the Trypoxylon. The larva of the cuckoo-fly transforms without cocoon to a pupa, 

 and in this state passes the winter. 



The succeeding five families, Mutillidse, Scoliidoe, Lapygidae, Pompilida3, and 

 Sphegidas, may conveniently be classed together under the head FOSSORIAL HY- 

 MENOPTERA, or, in common parlance, digger wasps, in contradistinction to the 

 true wasps of the family Vespidae. This term is a useful one, as it is often convenient 

 to be able to speak of these families collectively. The families Mutillidse and Scoliidae 

 are included under this heading, rather than separated under the name Heterogyna, 



