OETHOPTEEA. 559 



Acrydii are alwaj's laid iu rudely regular clusters, in the 

 ground." (Scudder.) 



The nervous system closely resembles that of the Neurop- 

 tera ; it is in all three stages composed of three thoracic, and 

 six or seven abdominal ganglia, extending the whole length of 

 the body, and united by double commissures. The splanchnic 

 system, or analogue of the gi*eat sympathetic nerve in verte- 

 brates, is highly developed in the Acrid ii and in Gryllotalpa, 

 having in front two pairs of ganglia, and posteriorly one or 

 two, while in the Blatiarioe and Pliasmida the single 

 nerve is most developed. 



Organs of hearing are stated by Siebold to occur in the 

 Acridii, consisting of two fossae or conchs, surrounded by a 

 projecting horny ring, and at the base of which is stretched 

 a membrane resembling a tympanum. On the internal surface 

 of this membrane are two horny processes, to which is attached 

 an extremely delicate vesicle filled with a transparent fluid, 

 and representing a membranous labyrinth. This vesicle is in 

 connection with an auditory nerve, which arises from the third 

 thoracic ganglion, forms a ganglion upon the tj'mpanum, and 

 terminates in the immediate neighborhood of the labyrinth by 

 a collection of cuneiform, stalf-like bodies, with very finely 

 pointed extremities (primitive nerve-fibres?), which are sur~ 

 rounded by loosely aggregated, ganglionic globules. The 

 Locustarice and Gryllidce have a similar organ, situated 

 in the fore legs directly below the coxo-femoral articulation. 

 M. Plensen confirms the accuracy of this description in 

 the " Zeitschrift fiir Wissenschaftliche Zoologie," vol. xvi, 

 1867, 



The highly developed alimentary canal has the crop (pro- 

 ventriculus) separated by a deep constriction from the oesoph- 

 agus, and the gizzard is provided internally with from six to 

 eight rows of horny denticulated plates situated on ridges, 

 with numerous smaller teeth between, so that the whole num 

 ber of teeth amount to 270. The stomach is of even width, 

 not usually making more than one-half of a turn, or one turn ; 

 its cardiac extremity is provided with from two to eight caeca. 

 The salivary glands are highlj^ developed, "consisting of two, 

 four, or six botryoidal masses, situated in the thorax, and hav- 



