131 



especially finding their way in great numbers to the flowers. These larvae are 

 small yellow mite-like creatures, elongated, narrow and flattened, with long 

 stout legs provided with simple claws, a short lateral seta to each abdominal 

 segment, and two longer and two shorter hairs at the apex of the last segment. 

 The spiracles of the third and fifth segments of this little creature are beau- 

 tiful objects for the microscope. These extremely active little larvas attach 

 themselves often in great numbers to the bees that visit the flowers to which 

 they have climbed, or indeed to almost any insect. When carried off by the 

 bee, and each species of Meloc appears to attack only one species of bee, to 

 its nest, the Meloe larva devours the egg of the bee, entering into its interior 

 to do so ; here it assumes a new form, being arched, cylindrical, with toothed 

 mandibles and short stout legs. It now eats the store of pollen bread that 

 had been collected by the bee for its own larva, and emerges in the following 

 spring, but is yet lean and hungry-looking when compared with the beetle 

 as usually met with, that is, after it has eaten abundantly of crowfoot, which 

 it does most voraciously. 



We shall see that the life history of Rhipiphorm is very similar to this, 

 excepting that Mctte is essentially a vegetable feeder ; Rhipiphorus, on the con- 

 trary, is carnivorous. 



A sketch of the economy and life history of the wasp will be useful as an 

 aid to understanding that of its parasite Rhipiphorus. Each nest of the wasp 

 is founded in the spring by a queen wasp which has lived through the pre- 

 ceding winter, dormant in some hollow tree, or some other place suitable for 

 hybernat ; on. At first the queen, unaided, constructs the nest and comb, col- 

 lecting the material of which it is made, and forming it into paper, and 

 building with it the cells. She collects the food for and tends the young 

 grubs, and continues to do this until she has reared a sufficient number of 

 worker wasps to perform all these duties, after which she never leaves the nest, 

 and merely lays eggs in the cells, which are afterwards entirely attended to 

 by the workers. Until August or September, although the nest has been much 

 enlarged, and may contain several thousand wasps, they are all workers, and no 

 queens (females) or drones (males) are raised. The queens are reared in the 

 most recently constructed comb, whose cells are much larger than the ordi- 

 nary worker comb, but which differs -from it in no other respect. Each layer of 

 comb is begun from a centre consisting of a few cells, and is increased by addi- 

 tions to its circumference, and as eggs are laid in each cell as soon as it exists, 

 the central cells contain the oldest grubs, until these have emerged, when eggs 

 are again laid in them, and it may happen in this way in a large piece of comb, 

 that the centre contains eggs for the third time, whilst the outer row has only 

 its first series, and round the centre there are concentric circles of wasp grubs 

 and pupaj of different ages. If we trace the history of an individual wasp, 

 we find that the egg is firmly attached by one end to the inner angle of 

 the cell. The newly hatched grub does not creep out of the egg-shell, but casts 

 it as a very delicate pellicle. It does not completely leave it, however, but 



