184 HOUSE, GARDEN, AND FIELD 



hardly to hang together till they are carefully examined. 

 In the quite distinct order of Rodents each of the three 

 finds its analogous form, as zoologists say. The porcupine 

 is analogous to the hedgehog, the field-mouse to the shrew, 

 the lemming, the mole-rat and others, not so well known, 

 to the true mole. Among the monotremes again, the 

 hedgehog-form is reproduced in Echidna. Affinity may 

 thus be disguised by adaptation to different modes of life, 

 and adaptation to the same mode of life may exist without 

 affinity. Think of other examples of the same kind. You 

 can easily find them among aquatic quadrupeds, among 

 birds and reptiles, among moorland plants, desert plants 

 and aquatic plants. 



XXXIV. THE HOUSE-CRICKET. 



Any naturalist who attends to insects, will be sure to 

 make acquaintance with the common house-cricket, and 

 may, if he dwells in the right part of the country, become 

 familiar with the field-cricket also. 



Crickets belong to the Orthopterous order, and have 

 biting mouth-parts, two pairs of wings of unequal texture, 

 the fore pair (wing-covers) being relatively stout and 

 opaque, the hind pair membranous and folded fan-wise 

 when at rest ; they go through no transformation, though 

 they gradually acquire wings, and they have no resting- 

 stage. Crickets are leaping insects, as the thickened thigh 

 on the hind leg and the angle which it makes with the 

 following joint show at a glance. They have long antennae, 

 and only three joints in the tarsus or foot. 



It is easy to tell a male from a female cricket, for the 

 female always has a long sabre-shaped egg-laying tube 

 (ovipositor) projecting from the end of the abdomen ; it 

 is used to pass the eggs into crevices, and in the house- 

 cricket is about half an inch long. No such appendage is 

 possessed by any male insect. 



