in SPHEGIDAE -- NYSSONIDES 123 



speciosus is a member of the Stizinae, a group recog- 

 nised by some as a distinct sub-family. It makes use, in North 

 America, of Insects of the geniis Cicada as food for its young. 

 Burrows in the ground are made by the parent Insect ; the cui: 

 is deposited on the Cicada, and the duration of the feeding-time 

 of the larva is believed to be not more than a week ; the pupa 

 is contained in a silken cocoon, with which much earth is incor- 

 porated. Riley states that dry earth is essential to the well- 

 being of this Insect, as the Cicada become mouldy if the earth 

 is at all damp. As the Cicada is about twice as heavy as the 

 Spliecius itself, this latter, when about to take the captured 

 burden to the nest, adopts the plan of climbing with it to the 

 top of a tree, or some similar point of vantage, so that during its 

 flight it has to descend with its heavy burden instead of having 

 to rise with it, as would be necessary if the start were made from 

 the ground. 



Sub-Fam. 7. Nyssonides. Labrum short; mandibles entire // 

 the outer edge; hind body usually not pedicellate; /////// 

 with the marginal cell not appendiculate. 



This group has been but little studied, and there is not much 

 knowledge as to the habits of the species. It is admitted to be 

 "impossible to define it accurately. It is by some entomologists 

 considered to include Mellinus, in which the abdomen is pedi- 

 cellate (Fig. 48), while others treat that genus as forming a 

 distinct sub-family, Mellinides. Kohl leaves Mellinus unclassified. 

 Gerstaecker has called attention to the fact that many of the 

 Insects in this group have the trochanters of the hindyaud middle 

 legs divided : the division is, as a rule, not so complete as it 

 usually is in Hymenoptera Parasitica ; but it is even more marked 

 in some of these Nyssonides than it is in certain of the parasitic- 

 groups. 



Mellinus arvensis is one of our commonest British Fossores, 

 and we are indebted to the late F. Smith for the following 

 account of its habits : " It preys upon flies, and may be commonly 

 observed resorting to the droppings of cows in search of its prey: 

 it is one of the most wary and talented of all its fraternity ; were 

 it at once to attempt, by a sudden leap, to dart upon its victim, 

 ten to one it would fail to secure it ; no, it does no such thing, 

 it wanders about in a sort of innocent, unconcerned way, amongst 



