THE DENIZENS OF AN OLD CHERRY TREE. 7 



to one. A male emerged with one pair of wings only and no 

 abdomen ; the fly, however, was very active and Uved for several 

 hours, and it was the only cripple observed. 



The numerous borings of this industrious insect prove a subject 

 of great interest. They are not formed by the grub for the sake of 

 its food, as in the case of the beetle previously described ; but 

 the mother Pemphredon, with her cutting and toothed mandibles 

 (Fig. 2, PI. II.), gnaws away the wood, and removes it with great 

 dexterity with her legs, which are armed with spines that act like 

 rakes (Fig. 5, PI. II.), thus toiling on alone until the required 

 burrow is ready to receive the fruits of her labours, and form a 

 home for her progeny which she is destined never to see ! She 

 now sallies forth on a hunting expedition among the Aphides, 

 which are captured, stung, and paralysed, and let us hope ren- 

 dered insensible. In this condition the prey is brought home and 

 closely packed at the end of one of the burrows in sufficient 

 quantity to provide food for one of her family while in its larval 

 state. An egg is now laid in this larder,-'^ and over all sufficient of 

 the wood debris is packed to form a partition, against which ano- 

 ther larder is stocked and another egg deposited, the process being 

 repeated until her egg-laying powers are exhausted, and now, her 

 mission being accomplished, she dies as the summer fades ; while 

 in their separate retreats her tiny progeny emerge from their egg- 

 cradles to find themselves surrounded with food, which, owing to 

 the prescient action of the parent, is preserved from decay until 

 the larvae are full grown, and no longer require a carnivorous 

 pabulum. In the perfect state these Fossores feed on the nectar 

 of flowers and the sap of plants— a most interesting fact, for here 

 we have a herbivorous insect hunting and providing food for its 

 carnivorous young ! In the larval stage P. lugubris is subject to 

 the attack of the larvae of an Ichneumon fly {Perithous varius, 

 Fig. 14, PI. II.), of which three specimens emerged from these 

 borings ; and we can only infer that the parent Ichneumon gained 

 access to the burrow while its occupants were in the larval stage, 

 when it deposited its egg near or in its future prey. 



* The remains of these larders consist chiefly of legs, heads, cornicles, 

 wings, and the extremities of antennae of aphides, some of which were sent to 

 Mr. H. C. A. Vine for identification, who kindly reported the genus to be 

 Siphonophora, and the species probably S. rosa and S. pisi. 



