XVIII A PARASITE— THE COCOON 245 



some which are occupied at the same time by the 

 larvae of the Hymenoptera and by other larvae — 

 strangers to the family and greedily sharing their 

 food. These strangers are smaller than the nursling 

 of the Bembex — shaped like a tear, and of the 

 colour of wine, from the food paste which can be 

 seen through their transparent bodies. Their number 

 varies from six to ten or more. They belong to a 

 kind of Dipteron, as may be perceived from their form 

 and from the pupae which one afterwards finds in 

 their place. The demonstration is completed by 

 bringing them up one's self in a box, where, fed daily 

 with flies, and laid on sand, they turn into pupae, 

 whence issue the following year little Diptera — 

 Tachinids of the genus Miltogramma. 



This is the Dipteron which, when lying in wait 

 near the burrow, awakens such alarm in the Bembex. 

 Her terror is only too well founded. This is what 

 happens in the dwelling. Around the heap of food 

 which the mother wears herself out in providing in 

 sufficient quantity, sit in company with the legitimate 

 nursling from six to ten hungry guests, who put their 

 sharp mouths into the general heap as unceremoni- 

 ously as if they were at home. Concord seems to 

 reign at table. I have never seen the legitimate 

 larva take offence at the indiscretion of the strangers, 

 nor observed these attempt to trouble its repast. 

 All keep themselves together, and eat peaceably 

 without annoying their neighbours. 



So far all would be well, were it not that a grave 

 difficulty arises. However active may be the mother- 

 nurse, it is clear that she cannot meet such a con- 

 sumption of food. She has to be incessantly on the 



