44 SUMMARY OF CURRENT RESEARCHES RELATING TO 



second maxillae (labium). The clypeus and labrum, however, remain 

 to be accounted for, and probably represent the tergal portion of the 

 antennary segment, the procephalic lobes forming its pleural portion ; 

 these latter become the epi cranium of the adult ; hence the head of 

 an adult insect is chiefly made up of the first, or antennary segment. 

 The so-called " occiput " is shown to be the tergal portion of the 

 fourth or labial segment ; it generally disappears in the adult, or 

 becomes soldered to the epicranium, but remains in Corydalus (a 

 Neuropterous insect) as the base of the head. 



The remainder of the original segments are obsolete, and take no 

 part in the formation of the epicranium in the adult. 



Protective Device employed by a Glaueopid Caterpillar.* — It 



is "well known that many caterpillars, e. g. those of the Arctiidse, 

 interweave their prickly hairs with their cocoons, thus not only ren- 

 dering the latter stronger and thicker, but also furnishing a kind of 

 protection in those species in which the hairs have an urticating 

 power. A novel and ingenious method of utilizing its hair for the 

 protection of the chrysalis is that employed by the larva of Eupomia 

 Eagrus, as described and figured by Dr. Fritz Miiller. Around the 

 slender- twig to which it intends to fasten its chrysalis, the larva 

 constructs from its hairs, before and behind itself, a series of whorls, 

 about six in number, the hairs in each whorl being vertically and 

 very densely fastened to the twig. The inside whorls are so fastened 

 that they incline over the head and tail ends of the pupa. Between 

 these two formidable rows of palisades the pupa rests safe from the 

 attacks of any small and unwinged enemy. 



Formation of Honeycomb.! — It is well known that the cells of 

 honeycomb aiford the largest possible space and the greatest strength 

 with the least possible expenditure of material ; but the subject 

 has not been properly investigated in a scientific manner. The earlier 

 researches of Maraldi and others at the commencement of the 

 eighteenth century showed that each cell in the honeycomb of bees 

 consisted of a six-sided column bounded in the middle layer of the 

 comb by a three-sided pyramid, and that the sides of the cells in 

 the deepest portion form with each other angles of 120°, and the 

 mathematical relations of the angles and sides of the cells to one 

 another were investigated. The actual way in which the bees form 

 the cells has been closely observed by Dr. K. Miillenhoif. 



A number of the insects, at least a dozen on each side, commence 

 to form the comb, and they are so arranged as to be exactly opposite 

 one another ; by mutual pressure therefore the lump of wax which 

 each bee carries in its jaws becomes pressed out to form a plate ; each 

 bee, however, avoids coming into contact with the bee in front, and 

 therefore the middle lamella of the honeycomb gets to be formed out 

 of as many pairs of parallel trapezes as there are bees on each side. In 

 a similar way the whole process of building the honeycomb was 

 observed, and the observation showed clearly that the wonderful com- 

 plexity and mathematical accuracy of the whole structure was not in 



* Kosmos, xii. (1883) p. 449 (fio;s.). Cf. Amer. Natural., xvii. (1883) p. 1289. 

 t Pfliiger's Arch. f. gesammt. Physiol., xxxii. (1883) pp. 589-618. 



