Platyptera 179 



on the delicate parts of the feathers or hairs, as well 

 as on the dried secretions of the skin. Their flattened, 

 wingless bodies are well adapted for such a life. The 

 eggs are attached to the feathers or hairs of the host, 

 and the young very closely resemble their parents. 



Two families of Mallophaga are recognised, com- 

 prising about looo known species (ill). 



Liotheidae. — The Lioihcldte are characterised by the presence of 

 four-segmented palps on the second maxills, and long two-seg- 

 mented and two-clawed tarsi on the legs. They are fairly active 

 insects, and when their host dies, they are able to go in search of 

 another. Most of tlie species live on birds, but many are attached 

 to mammals. 



Philopteridae. — The PhiloptiriJa: are more degraded than the 

 Liotheida;. The second maxills are destitute of palps ; the tarsal 

 segments are very short, and opposable to the shin, so that the 

 insect clings by its feet to the feathers of the host. With the ex- 

 ception of a single genus, the Philopteridse (fig. 97) are all found 

 on birds. They are incapable of travelling from one bird to another, 

 and perish soon after the death of their host. 



Both families of Mallophaga are world-wide in their distribution. 



Sub-Order B. Corrodentia. 



This sub-order includes insects readily separable 

 from the Mallophaga by the possession of fairly long 

 feelers — with ten or more segments ; and by the 

 absence of the degradation in structure which accom- 

 panies parasitism. They are terrestrial throughout life. 



There are three very distinct families which may be 

 considered separately. 



Embiidae. — The Embih/d.' are small insects of elongate form. The 

 feelers have from fifteen to twenty-four segments ; while the jaws 

 resemble those of Orthoptera, the maxillse of the second pair being 

 imperfectly fused together. The prothorax is small, the other two 

 segments of the fore-body are long and similar to each other; the 

 hind-body has ten evident segments whereof tlie hindmost bears a 

 pair of two-segmented cercopods. The wings of the two pairs 

 (when present) are closely alike; each wing has four longitudinal 

 nervures, the second and third of these only reaching the wing-tip, 

 and being connected by a few cross-nervules. There are three tarsal 

 segments ; the proximal segment on the front foot is provided with 

 glands whose secretion forms a silken thread, which is woven into 



