1912] Mnir and Kershaic — Development of Mouthparts in Homopfera 77 



11. Necrobia rufipes DeGeer. 



Clems rufipes DeG. Memoires pour servir a 1' Histoire des Insectes, V, 1775, p. 

 165, pi. XV, fig. 4. 



This cosmopolitan species was taken at Santarem, Itacoatiara, 

 Porto Velho and Madeira-Mamore R. R. Camp No. 39. 



THE DEVELOPMENT OF THE MOUTHPARTS IN THE 



HOMOPTERA, WITH OBSERVATIONS ON 



THE EMBRYO OF SIPHANTA. 



By F. INIuir and J. C. Kershaw, 

 Honolulu, Hawaii. 



The Revolution of the Embryo. 



The following observations were undertaken to see whether the 

 development of the head of a Homopteron was similar to that of 

 a Heteropteron and to observe if the "mandibular plate" of cer- 

 tain authors was of mandibular origin or not. As certain early 

 embryonic stages present features of interest we have included a 

 short description of them. 



The eggs of Siphanta acuta are long, cylindrical, flattened on 

 the ventro-anterior surface where the micropylar area is situated, 

 pointed at the anterior and rounded at the posterior end. The 

 chorion of the eggshell bears the more or less hexagonal honey- 

 comb impression of the follicle cells (epithelium) of the ovaries. 

 The micropylar area appears to be a modification of this hexag- 

 onal pattern, where the (apparent) cell- walls are more crowded 

 together and thus narrowed. The eggs are laid in batches of about 

 60 with the ventral surface uppermost, one overlapping the other 

 so that, except the last layer, only the micropylar area is exposed. 

 They are glued together with colleterial fluid and are difiicult to 

 get asunder without injury to the egg. The nymph, with the 

 aid of an egg-burster, cuts a straight slit down the centre of the 

 micropylar area to escape. 



Twenty-four hours after the egg is laid, the blastoderm is dis- 

 tinct and a thickening along the dorso-posterior area indicates the 

 primitive streak. At about the thirtieth hour the posterior end 



