200 
HYMENOPTERA. 
length, the forelegs often modified for digging. Males and females are 
superficially alike, the latter having a well developed sting. As in 
all Acnleata, there is no free life history and none are social, the female 
storing food for the young. The larva is a white soft grub, without legs 
and with a small head. Pupation takes place in a silken cocoon. 
Sphegids are the familiar digging wasps, whose prey consists of 
insects, stung to insure paralysis and laid up in this state in a suitable 
cell or burrow for the young to 
feed on. The process of stinging 
may be observed and is some¬ 
times accompanied by other 
injury to the prey to insure 
its helplessness. So far as is 
known, the prey is, when laid in 
the cell, helpless, but not dead, 
and remains so until the grub 
attacks it; how far the perman¬ 
ence of this paralysis is due to 
the action of the wasp and how 
far it is induced also by the 
conditions in the cell is not known ; a cricket stung by Sphex lobatus 
and laid up, presumably remains paralysed ; but that cricket taken 
out and kept under other conditions may die if kept too dry or may 
to some extent recover under favourable conditions of temperature, 
moisture, air and light. There is no reason to doubt that paralysis 
is caused primarily by injuries inflicted by the wasp, usually in the 
form of a sting or several stings, which are directed against the 
nervous system and induce paralysis. The student will find ac¬ 
counts of some species below and further accounts in the literature 
mentioned. Horne described the habits of Sceliphron (Pelopceus) 
madraspatanum F. S. lilineatus, Sm., S. violaceum F. (P. bengalensis, 
Smith), Trypoxylon rejector , Sm., Pison rufipes Sm., and P. (Pisonitus) 
rugosus, Sm. There is a large field here for an observer gifted with 
patience and perseverance to add to our knowledge of the habits of 
these important insects. The actual economic importance of the 
group, so far as it can be gauged, is great since most of the species 
destroy insects of economic importance. It is, however, very difficult 
