246 ENTOMOLOGY FOR MEDICAL OFFICERS 



crickets. It is a large one, and includes many insects that 

 are terribly destructive to vegetation. It is of hardly any 

 direct importance to the medical officer ; but indirectly it 

 concerns him, since in districts where the population is 

 immediately dependent on agriculture, the damage done to 

 growing crops by visitations of locusts may cause scarcity, 

 which may bring in its train the usual famine diseases. 



The Orthoptera are usually grouped in two suborders, 

 namely, (i) Cursoria (Lat. cursor =2. runner), in which the 

 hind legs differ but little from the other legs ; and (2) 

 Saltatoria (Lat. saltare = to leap), in which the hind legs are 

 longer and usually much stouter than the other legs, and are 

 used for leaping. 



Suborder Cursoria. 



This suborder includes five families, namely, earwigs, the 

 curious parasite Hemimerus, cockroaches, praying-insects, 

 and stick- and leaf-insects. 



Family Forficulida : Earwigs {haX. forjicula — a. pair of small shears). 

 Earwigs are easily recognised by the pair of strong pincers at the end 

 of the abdomen. The tegmina are short, and the wings are packed in a 

 peculiar manner, being folded first lengthways like a fan, and then 

 again crossways in reversed folds. In a good many earwigs the wings, 

 and in some the tegmina also, are absent. Earwigs gnaw flowers and 

 fruit, but they are also carnivorous. An Indian species with very long 

 pincers has been seen to use these organs for carrying prey. A 

 diminutive tape-worm of rats (which also occurs in man occasionally) 

 has been found in its cysticercus stage in an earwig. 



Family Hemiineridce. The one or two West African 

 species that constitute this family look something like 



^,=,„^^ , mand. 



a/^^SO maxp. 

 '. . y-'^\y^jP^^^- fnax. 

 'ib-P V ■■■ .•r'^feXSt^ \-lab.paIp. 



Fio. 114.— Head and Tarsus of a'cmimcnw, enlarged. 



wingless cockroaches, but the coxae are small ; there are 

 only 3 tarsal segments, and these have hairy, sucker-like 

 pads on the under surface ; the head is not inflexed, and 

 the mouth-parts (Fig. 114) are peculiar. The abdomen ends 



