274 INTRODUCTION TO ZOOLOGY chap. 



Family 3 : Gryllidab (Obickbts) 



Crickets resemble, in most of their characteristics, the 

 Long-horned Grasshoppers, though their tarsi are usually 

 three-jointed only. They differ also in the way in which the 

 tegmina lie flat, with the outer margin bent over the side of 

 the body. 



The House Cricket, or " Ciicket on the Hearth " {Gryllus 

 domesticiis), which used to be fairly common, has now become 

 much rarer. 



The Mole Cricket (Gryllotalpa vulgaris) is also rare in 

 England, though common in S. Europe. It is of special 

 interest because of its adaptation to an underground life, 

 living in burrows which it excavates for itself with its much- 

 modified front legs. 



Classification of the Orthoptera mentioned in Chapter XVIIL 



Sub-order 1. — Cursoria. Those which run along the ground, the 

 hind legs being very similar to the others. 

 Family 1. Blattidae. Cockroaches. 

 „ 2. Forficulidae. Earwigs. 

 „ 3. Mantidae. Praying Insects. 

 „ 4. Phasmidae. Leaf and Stick Insects. 

 Sub-order 2. — Saltatoria. Those in which the hind legs are much 

 bigger and stronger than the others, being 

 adapted for leaping. 

 Family 1. Acridiidae. Common Short-horned Grasshoppers, 

 „ 2. Locustidae. The Long-horned Grasshoppers. 

 „ 3, Gryllidae. Crickets. 



Practical Notes 



1. The Cockroach is the insect most generally used, in a practical 

 zoology course, as an introduction to the typical structure, both 

 external and internal, of an insect, and full directions for its dis- 

 section are given in almost any practical zoology book. Here, 

 therefore, it is sufficient to suggest that living specimens be captured, 

 and their external form and habits studied, the points men- 

 tioned in the previous chapter being carefully verified. To kill a 

 cockroach for more detailed study, drop it into boiling water ; this 

 causes death instantaneously. The mouth-parts and segments of 



