1921] Wheeler: Some Social Beetles 67 



suggestive. It will be noticed that his Figs. 1, 2, 5, 8, 16, Plates 

 VII and VIII etc. show that the tongue is large and flat like a 

 spatula or ladle and well-adapted for receiving the globules of 

 coccid excrement. The labial palpi are very small and 2-jointed, 

 but the maxilla is large, with extensive stipital articulation and 

 a large lacinia tipped with a claw-like tooth and fringed with 

 stiff hairs along the medial border. The maxillary palpi are 

 long and 3-jointed and the large articular membranes of the 

 separate joints suggest great mobility. The antennae are un- 

 usually interesting (Plate VII, figs. 1, 2, 5, 7). Though they 

 consist of only three joints, the second is greatly elongated and 

 distinctly drum-stick-shaped, the apical joint being much reduced 

 to form merely a sensory cap for the second joint. Now this 

 drum-stick-type of antenna is precisely the one found in a long 

 series of symphilic ant-guests of the Coleopterous family Clavi- 

 geridae (Fustiger, Rhynchodaviger, Adranes, etc.), which use 

 their antennae for soliciting liquid food from their hosts. Dr. 

 Boving's figures of other larval Silvanids and of genera belong- 

 ing to closely allied genera of the Cucujid complex, namely 

 Cathartus (Plate VIII, fig. 12), Nausibius (Plate VIII, fig. 18), 

 Dryocera (Plate IX, fig. 33), Telephanus (Plate X, figs. 34, 37) 

 and Scalidia (Plate X, fig. 39), show very different conditions. 

 Thus we may say that the antennae and maxillae of the Coccido- 

 trophus larva are specially adapted to their active role of solicit- 

 ing and the labium to its passive, spoon-like role of receiving the 

 liquid excreta of the Pseudococcus. 



The question naturally arises as to the function of the 

 anterior and posterior ostioles, which, as I have shown, are 

 highly developed in Ps. bromeliie, and the probability of their 

 secreting substances that may be ingested by the beetles. Un- 

 fortunately I did not know of the existence of the ostioles while I 

 was at Kartabo. My attention was called to them by Prof. Mac 

 Gillivray several months after my return. I feel very confident, 

 nevertheless, that these organs in Ps. bromeliie cannot have the 

 function ascribed to them by Sulc in Ps. farinosus. I have so care- 

 fully watched the coccids of all ages that I could not have over- 

 looked the emission of orange-yellow droplets from the ostioles 

 or of any sticky liquid that would glue up the appendages of 

 small insects. The smallest beetle larvae are so delicate that 



