XXII CEPHIDAE 505 



wings is small but distinct. The female bears a saw at the 

 extremity of the body, but it is covered by two flaps ; these 

 form a short, terminal projection. Although too much neglected, 

 the Cephidae are really of great interest 

 as being of more imperfect or primi- 

 tive structure than any of the other 

 families of Hymenoptera. The larval 

 history has been traced in several 

 species. C. pygynaeus is sometimes very 

 injurious to corn crops on the con- 

 tinent of Europe, and even in our own 

 country its effects in this respect are 

 considered to be occasionally serious. 

 The eg-g is laid in the stem of the corn 

 plant ; the larva soon hatches and eats 

 its way upwards in the stem. It is a soft Fig 340.-(7ei.7.,|. pymaeMs. 



J -t Upper ngure, larva ; lower, 



grub, apparently footless, but really pOS- female imago. Britain. 



sessing six small projections in place of ^ 

 thoracic legs. It occupies all the summer in feeding, and when 

 full fed and about to prepare for its metamorphosis, it weakens 

 the stem by a sort of girdling process below the ear ; it then 

 descends in the stem to near the root, where it constructs a 

 transparent cocoon, in which it passes the winter as a larva, 

 changing to a chrysalis in the month of May, and completing 

 its development by appearing as a perfect Insect shortly there- 

 after. The girdlin^^peration is very injurious, and causes the 

 corn stem, when ripe or nearly so, to break in two under the 

 influence of a strong wind, so that the ears fall to the ground. 



The history of C. integer has been given by Eiley. This 

 Insact attacks the young shoots of willows in North America. 

 Eiley states ^ that by a wonderful instinct the female, after she 

 has consigned her egg to the twig, girdles the latter, preventing 

 it from growing any further, and from crushing the egg by so 

 doing. The larva after hatching eats downwards, sometimes 

 destroying a length of two feet of the twig ; when full grown it 

 fills the bottom of the burrow with frass, and then previous to 

 making its cocoon eats a passage through the side of the shoot 

 about a quarter of an inch above the spot where the cocoon will 

 be placed, thus making it easy for the perfect Insect to effect its 



^ Insect Life, i. 1888, p. 8. 



