644 THE STUDY OF INSECTS. 



cases the Aphids or scale-insects are huddled together on a 

 branch, from which they are deriving their nourishment, and 

 are completely covered by the " cow-shed " built by the ants. 



Superfamily SPHECINA (Sphe-ci'na). 

 The Fossores (Fos-so'res) or Digger-wasps. 



There are several closely allied families of the Hymenop- 

 tera that are usually classed together as the Fossores 01 

 Digger-wasps. These names refer to the fact that most 

 of these insects make nests for their young by digging 

 burrows in the ground or in wood. Many true wasps and 

 bees have similar habits, but these insects differ in appear- 

 ance from the Fossores in the following easily seen charac- 

 teristics : The true wasps when at rest have their wings 

 folded like fans, while the digger-wasps have their wings 

 lying flat above the body. The bees have the basal segment 

 of the tarsi of the hind legs flattened for carrying pollen, 

 while the digger-wasps have legs fitted only for digging and 

 walking. 



The Fossores are all solitary in their habits, that is, each 

 female makes provision for her young. The adults are very 

 fond of the warm sunshine, and may be seen flitting about 

 flowers in the tropical heat of the noontide. As in most 

 Hymenoptera, the male dies early, leaving the entire work 

 of the nest-building and family cares to the female ; however, 

 she seems entirely equal to her responsibilities. She burrows 

 in the ground or in wood, or utilizes the forsaken burrows 

 of other species, or builds in the ready-made cavities of 

 reeds or straws, or constructs a tube out of mud. The nest 

 thus made is provisioned with spiders or with insects, which 

 are not killed, but stung until paralyzed. The prey thus 

 treated remains alive a long time, but is helpless. The egg 

 is laid with this provision, and then the opening of the tube 

 sealed up securely. When the larva hatches it finds nicely 

 preserved food right at hand sufficient to nourish It during 

 its growth. 



