274 



AN INTRODUCTION TO ENTOMOLOGY 



The antennae are moniliform; in the winged adults the number 

 of segments varies in different species from twelve to twenty-five or 

 more. In newly hatched nymphs the number of antennal segments 

 is less than in the later instars. 



The members of the winged sexual caste have pigmented compound 

 eyes and a pair of ocelli. It is commonly stated that both the workers 

 and soldiers of termites are blind; but in some species the soldiers 

 have compound eyes; these, however, are not pigmented. There is 

 an African species, the marching termite, in which both workers and 

 soldiers possess eyes (Fuller '12). 



The median ocellus is wanting in termites; but in many forms 

 there is in its place a more or less distinct opening of a gland, the 

 frontal gland, whose secretion is used for defense; this opening of 

 the frontal gland is termed the fontanel or fontanelle or fenestra. 



Fig. 310. — Wings of Termopsis angiisticollis. 



The wings are long and narrow, and, when folded on the back of 

 the insect, extend far beyond the end of the abdomen. In the Aus- 

 tralian genus Mastotermes, the anal area of the hind wings is broadly 

 expanded; in other termites the fore and hind wings are similar in 

 form (Fig. 310). In each case, the veins of the anterior part of the 

 wing are greatly thickened and those of the middle portion reduced 

 to indistinct bands or to narrow lines. Regular cross- veins are lack- 

 ing, the membrane of the wings being strengthened by an irregular 

 network of slightly chitinized wrinkles. The wings are deciduous, 

 being shed after the swarming flight. The shedding of the wings is 

 facilitated by the presence in each wing, except in the hind wings of 

 certain genera, of a curved transverse suture, the humeral suture. 



