THE STICK AND LEAF INSECTS. 



131 



antennae of variable length ; the eves are hemispherical, and the ocelli are either three in number 



or altogether wanting. The labrum is deeply notched ; the mandibles are short and powerful ; 



the maxillre and labium are formed much as in the Mantidae, but the outer lobes of the labium 



are very much larger than the inner ones. A striking contrast to the Mantida? is found in the 



prothorax, which is very short ; the mesothorax, on the contrary, is elongated, and is indeed the 



longest of the three thoracic segments. 



Both tegmina and wings ai'e often .r^S^fe^ I/ ' 



absent, either in the females or in both 



sexes ; when developed, the former are 



short, and only cover a portion of the 



true wings, which present a remarkable 



structure. The front or outer portion 



of each wing, from the base to the apex, 



is of a leathery texture, resembling that 



of the tegmina ; the membranous hinder 



portion of the wing shows the usual 



fan-like arrangement of primary veins, 



and the whole of this part, when shut 



up, is concealed beneath the leathery 



anterior area, which thus acts the part 



of a supplementary wing-cover. The 



abdomen shows nine segments on the 



back, but in the females only seven, 



and in the males eight rings are recogr 



nisable below, and this is due to the 



circumstance that in the former the last 



ventral plate but two, and in the latter 



the last but one, is usually produced so 



as to conceal the actual apex, which is 



furnished with a pair of unjointed cerci, 



sometimes knobbed or leaf-like in their 



form. 



The eggs of the Phasmidse are few 

 in number, and are deposited singly, 

 the females caiTying them about in 

 the shovel-like process of the seventh 

 abdominal half-ring for some time before 

 quitting them. The eggs are of large 

 size and covered with a horny shell, at 

 one end of which there is a distinct 

 operculum. The sides are variously or- 

 namented with wavy lines, and the general surface is more or less punctured. In the "West Indies 

 the hatching of the eggs has been observed to take place in from seventy to one hundred days after 

 their deposition. 



The number of species of this family is not very large ; by far the greater part of them are 

 inhabitants of the warmer regions of the earth, and they seem to increase in magnitude especially 

 the nearer their home lies to the equator. The species are much more numerous in the eastern 

 than in the western hemisphere, and in both a few species pass into temperate regions. Two occur 

 in the south of Europe, the best-known being Rossi's Stick-insect (Bacillus rossii), a brown wingless 

 form frcm two inches to two inches and a half in length, found in Italy and the south of France- 

 Some of the tropical species are the largest of insects, a winged Australian species (Acrophylla titan) 

 attaining a length of ten inches, whilst an apterous Brazilian species (Bacteria aurita) is of equally 

 gigantic dimensions. The general coloration of the species exhibits various shades of brown and 



BACILLUS ROSSII. 



