378 



NATURAL HISTORY. 



and generally presents rather less divergence from her partner than in the more typical genera just 

 referred to. Nevertheless, there are important differences between the sexes ; the male has long and 

 nearly straight antennae, while those of the female are short and bent ; the female is generally larger 

 and more robust than the male ; and they frequently differ in coloration, sculpture, hairiness, and 

 other characters to which we cannot here refer. The Scolue are large and powerful Hymenoptera, 

 some of them attaining a length of two inches, and they are armed with very formidable stings. They 

 chiefly inhabit warm countries, and their larvre usually feed upon the grubs of large Beetles. 



The British forms of this group belong to a distinct genus (Tiphia), and are of small size. They are 

 not abundant. Mi*. F. Smith notices the frequent occurrence of the commonest of them (Tiphia femorata) 

 under the droppings of cattle, from which he was led to suspect that they might be parasitic upon the 

 larva of some coprophagous Beetle. 



FAMILY FORMICID^E. 



In this family, which includes the various species of Ants, we have to do once more, and for the 

 last time, with social insects organised after the fashion of the Bees and Wasps that is to say, in 

 which the community is permanently made up of infertile females, or workers, with one or more perfect 

 females for egg-laying purposes, and only at a certain season of a larger number of females and males. 

 As in the case of the Hive Bee, the communities of Ants are generally permanent. The economy of 

 these insects presents some of the most interesting phenomena that the study of zoology has to offer, 

 and the writer's difficulty is to select from the mass of materials extant what will suffice to give 

 some notion of the natural history of the group. 



Even the character that must be given of the family is a complex affair. The males and females are 

 winged on their emergence from their cocoons ; the workers are always wingless. After the nuptial 

 flight the males die, and the females drop, or even pull off their wings ; but the latter have the 

 thorax broad, and of the ordinary Hymenopterous type, with the meso-thorax much developed for the 

 support of the large anterior wings. In the workers, on the contrary, the whole thorax is slender, 

 and the prothorax is the most developed segment. In the males and females the head is comparatively 

 small ; in the workers larger ; and in many cases two forms of workers exist one with a head of 

 ordinary size, the other with this part wholly out of proportion to the rest of the body, and armed 

 with formidable jaws. These large-headed workers are commonly called " Soldiers," and their function 

 is supposed to be to fight in defence of the nest. The antennse are generally kneed, with a long first 

 joint, except in the males of some types, in which the first joint is not much elongated, and the 

 geniculation is inconspicuous. The eyes are large in the males and females, always small and some- 

 times rudimentary in the workers ; and the ocelli, which are always present in the males and 

 females, are generally entirely wanting in the workers. In the wings, there is usually only one 

 submarginal cell, never more than two. The first, or first and second, segments of the abdomen form 

 a stalk, or petiole, very distinctly separated from the rest of the abdomen, which is ovate, heart- 

 shaped, or sub-globular in form ; and these segments bear a knot, or transverse scale, the presence 

 of which is one of the most easily-recognisable characters of the family. The females and workers 

 frequently possess a regular sting, which they use vigorously in. their own defence. Others have no 



sting, but most of these 

 possess glands, secreting an 

 acrid fluid containing formic 

 acid, which they can. inject 

 into the wounds produce! 

 by their mandibles. 



The Ants are generally 

 small and often minute 

 insects, which swarm in all 

 parts of the world, but are 

 most abundant, both in 



species and individuals, in tropical countries, where also the largest forms occur. The number of 

 described species is probably over a thousand, but the total number must be considerably greater, 

 if Mr. Bates is correct in his estimate that not less than 400 species inhabit the valley of the Amazon. 



Worker. 



WOOD ANT. 



