66 



PSYCHE. 



[April 1894. 



species found in Kansas and otlner 

 western states — Ammophila yarroxvi 

 Cr. 



A single caterpillar usually suffices 

 for the food supply of a single wasp- 

 larva but this species brought cater- 

 pillar after caterpillar "till four or five 

 of them have been stored up for the sus- 

 tainment of her future offspring." Dr. 

 Williston says : — 



The things that struck us as most remark- 

 able was the most unerring judgment in the 

 selection of a pebble of precisely the right 

 size to fit the entrance and the use of the 

 small pebble in smoothing down and packing 

 the ^oil over the opening, together with the 

 instinct that taught them to remove every 

 evidence that the earth had been disturbed. 



In Florida I have seen Ammophila 

 cementaria Smith preying upon a half 

 growri Sphinx larva, which after para- 

 lyzing it seized bv its large jaws just 

 back of the head ; and as the larva 

 was too heavy for it to fly with, it strad- 

 dled it and then dragged it oft" to its cell, 

 moving forwards. 



Family XIII. Pompilidae. This 

 family is well represented in our fauna 

 by 10 genera and 137 described species, 

 the majority of which seem to prey 

 entirely upon spiders. 



In the American naturalist for 1SS7, 

 Dr. G. Lincecum has given us a most 

 interesting account of probably our 

 largest species, Pefsis formosiis Say, 

 known in the South as "The tarantula 

 killer." It preys upon ]\I\>gale hentzii 

 Girard and Dr. Lincecum, in speaking 

 of the eftects of the sting upon the 

 spider, says : — 



The effect of the introduction of its venom 

 is as sudden as the snap of the electric spark. 

 The wasp then drags it, going backwards, to 

 some suitable place, excavates a hole five 

 inches deep in the earth, places its great 

 spider in it, deposits an egg under one of its 

 legs, near the body, and then covers the hole 

 very securely. 



Just as is found to be the case among 

 the true bees, some of the genera being 

 parasitic or inquilinous on those of 

 some of the others, so in this family we 

 have at least one that is parasitic — the 

 genus Ceropales Latreille, which lives 

 in the cells of the others. St. Fargeau, 

 as quoted by Westwood, seems to have 

 been the first to observe this curious 

 habit, "having often observed the 

 females of this genus enter backwards 

 into the nests of some of the real 

 fossorial species, which he considered 

 a certain proof that their object was to 

 deposit their own eggs therein." 



This parasitism has been confirmed 

 in America by Walsh and Riley, who 

 have bred Ceropales rujiventris from 

 the cells of Agenia bombvcina Cr. and 

 other Ageniae. 



The genus Agenia Schiodte also 

 preys upon spiders. Walsh and 

 Riley in Amer. ent., vol. i, p. 131 have 

 figured and described the thimble- 

 shaped cells of four of our species — 

 Agenia bomhycina Cr., A. corticalis 

 Walsh, A. architecta Say an<l A. 

 mellipes Say — built under old bark of 

 standing trees or under logs and stones. 



From these cells, besides the Cero- 

 pales already mentioned, Walsh bred a 

 Chalcid-fly Fteromalus sp. and Ospry- 

 nochotus junceus Cr. 



