412 SYNOPTIC COLLECTION. 



wings in this fashion, and the subject becomes more 

 interesting when we consider that "it is probable that the 

 majority of the individuals of this species may never make 

 use of their organs of flight or go through the complex 

 process of unfolding and folding them." x If this is the 

 case this species of earwig is an illustration of an animal 

 that possesses absolutely useless organs. These organs 

 occur, however, in an order of insects all of whose mem- 

 bers have vestigial fore wings, and many of whose members 

 are without either pair of wings. One may, therefore, 

 reasonably predict that in time Forficula auricularia Linn., 

 will be wingless. 



The forceps which have given the name of Forficulidae 

 to the family probably represent the cerci of many insects. 

 They vary greatly in form from symmetrical to distorted 

 organs and little is known in regard to their function. It 

 is now probable that the peculiar insect, Hemimerus. tal- 

 poides Walk. (PI. 1002, fig. i, young; fig. 2, adult), is a 

 near relative of Forficula. According to the observations 

 of Hansen, 2 this insect has not four pairs of mouth parts, 

 as has been stated, but the normal number of three pairs. 



Hemimerus is a blind, wingless creature, that is found 

 living among the hairs of the rat, Cricetomys gambianus, 

 Waterh. Its development is accelerated, so that it brings 

 forth living young, but it differs from other viviparous 

 insects by giving birth to only one at a time. Probably 

 several days intervene between the birth of the small 

 number of offspring. Fig. i represents the young as 

 taken from the mother, showing the coiled position 

 and the ragged end of a process, extending from the 

 neck, which Hansen thinks connects the embryo with 

 the mother. When uncoiled the young Hemimerus is 

 nearly as large as the parent, and differs from it only 

 in the number of antennal joints and in the structure 

 of the posterior abdominal segments. 



'Sharp, Cambridge Nat. Hist., V, 1895, p. 207. 

 J Ent. Tidskr., XV, 1894. 



