56 THE HEAD. 



chapter on the scales, by my friend Mr. Beck, who has 

 studied them carefully, and than whom no one is more 

 competent to speak on the subject. 



TJie head. 



The head does not generally show any traces of 

 segmentation. In most cases it is somewhat com- 

 pressed from above and below ; in others, on the 

 other hand, as in Smynthurus, from in front and 

 behind, thus being, like the rest of the body, increased 

 in height at the expense of the length. In Leindocijrtus 

 th^ head is attached to the body at an angle, and in 

 some species of that genus the thorax projects so much 

 forwards that when the animal is seen from above the 

 head is completely hidden. The hairs or scales, as the 

 case may be, on the head, resemble those on the 

 general surface of the body. 



Laboulbene has called attention^ to a curious organ, 

 which he observed in Lipura mariUma, and which, 

 from its position on the surface of the head — imme- 

 diately in front of the eyes — he proposed to call "organ 

 prostemmatique ou ante -ocula ire." Inasmuch, how- 

 ever, -as a corresponding organ occurs in some species 

 where the eyes are wanting, Tullberg has suggested," 

 and I think with reason, that the term " post-antennal " 

 is, on the whole, more convenient. 



Laboulbene thus describes this organ in Lipura mari- 

 Uma (PI. LXY, fig. 15). It is formed, he says, " par des 

 espaces colores tels que les represente la figure 7 ; leur 

 couleur est tres-noire. Le nombre des cercles rapproches 

 varie de 7 a 8, le plus ordinairement il y en a 7, mais 

 je dois noter que j'en ai trouve parfois 8 d'un cote et 

 7 de I'autre. Sur les jeunes iudividus, la disposition 

 est tres curieuse, la figure 9 en donne une idee ; il 

 existe alors 22 a 24 espaces comprimes et serres les 

 uns contre les autres, avec un espace central libre ; le 

 tout rappelle la forme du fruit chez les plantes 



1 ' Ann. Soc. Eut. de France,' 186-i, p. 711. 



- ' Om Skandiuavisken Poduiider,' Upsala, 1869, p. 1-4. 



