234 The Orders of Insects 



leaf-fragments, etc., with a silk lining; the pups, which have 

 three or four free segments, find protection in these cases, and the 

 worm-like females without feelers, jaws, legs, or wings, also live 

 and die in them. The free-flying males have strongly-toothed 

 comb-like feelers, but no functional jaws. The wing-neuration is 

 of the Zygjenid type, but there is a complex anastomosis between 

 the three anal nervures of the forewing. The wings are usually 

 grey or dusky in colouration. 



Heterogynidae. — The Heterogynlda are a family containing a 

 single south European genus. These insects resemble the Psychids 

 in appearance and habits, but the larvje do not form cases. The 

 female emerges from the cocoon to pair, but remains attached to 

 the ventral face of the pupa-skin, and withdraws again into the 

 cocoon for the purpose of laying her eggs. 



Cossidae. — The Couidti: are a small but universally distributed 

 family of rather large moths with all parts of the jaws very small or 

 vestigial, no food being taken in the perfect stage. The wing- 

 neuration is of the Zygsenid type, but the forking of the main median 

 nervure in the discoidal cells of all the wings is characteristic (fig. 125). 

 The larvs with the usual five pairs of prolegs feed within the stems of 

 plants, often in the wood of trees. The pups with three to five free 

 segments are protected in cocoons made up of chips of the food plant, 

 exceptionally in earthern cocoons. The species are most numerous in 

 the tropics ; in our islands three only occur, of which the " Leopard " 

 moth Zeu-zera pyrina (fig. 1 28) and the " Goat " (^Cossus cossui) are well 

 known. 



Sesiidae. — The SesHda or Clearwings are a large family of some- 

 what small day-flying moths with narrow wings which are for the 

 most part without scales. They have clubbed feelers, well-developed 

 first maxillz without palps, and a frenulum. In wing-neuration they 

 differ from all the preceding families ; three anal nervures are present 

 in the hindwing, but one and a trace of a second only in the fore- 

 wing. The second of the three median nervures in the forewing is 

 midway between the other two, the nervures generally coming off from 

 the cell at equal distances from each other; there is no sub-costal 

 nervure in the hindwing. Many of the Clearwings are much like 

 Hymenoptera in appearance. Their caterpillars, with five pairs of 

 prolegs, feed within the wood of plants. The pupa with three or 

 four free segments remains within its cocoon of chips until the time 

 of emergence comes, when it makes its way partly out of the food- 

 tree by means of the spines on its hind-body segments. 



Tortricidae. — The TortrhidiE are a very large family of small 

 moths, agreeing in most structural points with the Sesiidae. In 

 the hindwing the sub-costal nervure is, however, always present and 

 the second anal nervure is forked at the base. The feelers are not 

 swollen ; the first maxillae are usually well-developed though their 

 palps are wanting ; the palps of the second maxillae end bluntly. The 

 larv£E, with five pairs of prolegs, feed within the tissues of plants, or in 



