390 Mr. F. Smith on Wasjys and their Habits. 



of them ; and I have found also an egg attached to a single 

 fly, that being all that was stored up. These insects appear 

 in the autumn, when they can usually store up the required 

 amount of food without interruption ; but they must occasion- 

 ally be hindered in their work by rainy weather ; and as the 

 egg hatches usually in five or six days, it must occasionally 

 happen that the store has to be completed at a time when the 

 larva is feeding on the first fly or flies that were deposited. 

 I do not advance this as an instance in which a solitary sand- 

 wasp feeds its larvse periodically, but as one in which the spe- 

 cies deviates from the general rule that obtains : the fossorial 

 tribe of insects usually lay up the requisite store of food before 

 they deposit an egg upon it. 



The habits of a species of the genus Sphex (being one not 

 found in this country, but comprising some of the largest and 

 handsomest hymenopterous insects) are very interesting. The 

 economy detailed is that of Sphex ichneumonia : this insect 

 burrows into gravelly banks and hard pathways, and stores up 

 a single grasshopper to nourish its future offspring : this is an 

 additional instance recorded that shows the great diversity 

 that frequently occurs in the economy of species belonging to 

 the same genus. Mr. Gosse has most graphically described, 

 in his ' Sojourn in Jamaica,' published in 1851, the economy 

 of a large species of Sphex that stores up the caterpillar of a 

 moth. 



In my published notes on the economy of the genus Gerceris 

 I have recorded the fact of my having captured C. interrupta 

 storing up the little beetle Ajrion rufirostre j and G. arenaria 

 is well known to prey upon various species of Curculionidae : 

 I have at one time observed C. labiata conveying Curculio- 

 nidae to its cells, and at another selecting Haltica tabida. G. 

 ornate,) differing more widely in its choice of provision, selects 

 species of the short -tongued bees, Halictus rubicundus or H. 

 cylindricus being usually its prey. 



The same species of Fossor does not, therefore, at all times 

 select the same kind of prey : thus Shuckard records the fact 

 of AmmopMla viatica storing up spiders ; the same habit has 

 been observed by the Rev. A. Matthews. I have several times 

 observed the same species of Sp>hex conveying a Lepidopterous 

 larva, but never detected it with a spider. 



Another instance of variation in the selection of food may 

 be adduced : Tachytes pompiliformis, a most abundant British 

 insect in most sandy situations, frequently stores up a sandy- 

 coloured Lepidopterous caterpillar, but as frequently may be 

 observed preying upon the pupae of grasshoppers. 



Mr. Walsh gives interesting histories of some genera with 



