782 AN INTRODUCTION TO ENTOMOLOGY 



The cruciate bristles. — A pair of bristles on the lower part of the frontal vitta, 

 directed inward and forward. 



The facial bristles. — A series of bristles on either side borne by the vibrissal 

 ridge, above the vibrissa (Fig. looo, fa.). 



The facio-orbilal bristles. — Bristles borne on that portion of the face on each 

 side next to the orbit, the so-called gena. 



The frontal bristles. — A row of bristles on each side on the boundary line be- 

 tween the frontal vitta and the genovertical plate. (Fig. lOOO, fr.) the uppermost 

 of these, from one to foiu" in number, are termed the ascending frontal bristles; 

 the lower ones, which are often directed across the frontal vitta, are termed the 

 transfrontral bristles. 



The fronto-orbital bristles. — -A bristle or bristles on the genovertical plate, 

 immediately below the vertical bristles. (Fig. looo, fo.). So named because 

 they are on that part of the so-called front next to the orbit. 



The lateral facial bristles. — One or two bristles sometimes present on the sides 

 of the face below, towards the eye. 



The lower fronto-orbital bristles. — These are situated on the lower part of the 

 genovertical plates near the eyes and are not quite in line with the fronto-orbitals. 

 They are not of f i equent occurrence. 



The ocellar bristles. — (a) The greater ocellars or the ocellar pair, a pair of bristles 

 on the ocellar triangle ]ust back of the median ocellus (Fig. lOOO, g. o.). (b) The 

 lesser ocellar bristles, from three to twelve pairs of bristles, usually inserted in two 

 parallel lines, sometimes in four, which begin very close to the insertion of the 

 greater ocellar bristles and extend backward a variable distance (Fig. lOOO, /. o.). 



The occipito-central bristles. — A pair of bristles on the upper part of the occiput 

 just below and almost in line with the inner vertical pair. 



The occipito-lateral bristles. — A pair of bristles borne, one on each side, a 

 little back of the outer vertical bristles. 



The orbital bristles. — See fronto-orbital bristles. 



The postorbital bristles. — See cilia of the posterior orbit. 



The postvertical bristles. — The hinder pair of the lesser ocellar bristles. 



The preocellar bristles. — A pair of small bristles sometimes found below the 

 median ocellus. 



The transfrontal bristles. — See frontal bristles. 



The vertical bristles. — Two pairs of bristles, an inner and outer pair, inserted 

 more or less behind the upper and inner corners of the eyes (Fig. looo, ve.). 



The vibrisscB. — A pair of stout bristles, one on each side of the face, near or a 

 little above the oral margin (Fig. lOoo, vi). These are the longest or strongest of 

 the bristles borne on the vibrissal ridges. 



THE THORACIC SUTURES 



The transverse suture. — The suture between the prescutum and the scutum of 

 the mesothorax. 



The notopleural or dorsopleural suture. — The suture on each side separating 

 the mesonotum from the pleurum of the mesothorax. 



The mesopleural suture. — The suture on each side separating the episternum 

 and the epimerum of the mesothorax. 



The sternopleural suture. — The suture on each side separating the mesopleurum 

 and the sternopleurum. 



THE PLEURAL DIVISIONS 



The propleura. — The pleura of the prothorax (Fig. looi, pr.). 



The notopleura. — A sclerite on each side at the end of the transverse suture in 



