366 Miscellaneous. 



The globe is so placed that the eyes form a solid part of it, and 

 thus furnish a support for the whole apparatus. 



Besides the two eyes the only visible external organs are : a. the 

 last joints of the antennae ; b. the two horny, bowed palpiform 

 organs of the mouth ; and c. the proboscis. Everything else on the 

 head, except the bristles of the antennae and of the margins of the 

 eyes, disappears, and all the visible organs exhibit a change of posi- 

 tion. Thus the antennae occur on the side of the globe opposite to 

 the eyes, or quite in front. Only the last joint of each projects from 

 the globular head, on the surface of which they form as it were a 

 double hook directed downwards. They still however retain some 

 power of movement, and the fly appears to employ them in various 

 ways. The proboscis is directed obliquely backwards, below the 

 eyes ; it also retains some power of motion, and the fly can elongate 

 or contract it at pleasure. It appears to be an important part of the 

 apparatus, serving to press the globular head forwards, or rather to 

 give it a firm support in the pressure which it exerts upon the 

 obstacles before it. 



The two horny palpiform organs which lie between the antennae 

 and the mouth are also of importance in these operations. They 

 form a pair of hooks turned downwards and resting with their con- 

 vex sides against the globular head, so that as this expands their 

 extremities are pressed into the larva-skin, where they produce the 

 commencement of the transverse cleft of the aperture, which is after- 

 wards completed by the general expansion of the head. 



Besides this transverse cleft in the larva-skin, there is usually a 

 second crack running from the apex and dividing the cap which is 

 thrown ofl^, into two nearly equal portions : this is produced by the 

 wedge-like action of the antennae. 



When the expansion of the head has reached its maximum, it is 

 maintained for a few seconds, and then the head again contracts ; 

 but if it has not done its business sufliciently, it is again dilated until 

 the desired result is obtained. In this way the author observed that 

 a Tachina which he had enclosed in a narrow glass tube, tried more 

 than a hundred times to expel the cork by the expansion of its head. 



The expansion of the head commences by a prolongation of the 

 front of the face between the angles of the eyes : this forms a conical 

 point, having the antennae at its apex. The object of this is suffi- 

 ciently apparent : the fly can introduce this point into small holes 

 and crevices in the obstacles which interpose between it and the open 

 air ; these are then enlarged by the globular expansion of the head, 

 which is doubtless retained in its situation by the action of the 

 antennae. — WiegmanrCs Jrchiv, xxi. p. 189. 



On the apparent Absence of a Nervous System in the Nemoptera 

 lusitanica. By M. Leon Dufour. 



The author states that in exarhining numerous specimens of the 

 Nemoptera lusitanica, a species of Neuropterous insect abundant in 

 Spain and Portugal, he was unable to find any trace of a nervous 



