18 THE RICE GRASSHOPPER 



found in the same stage as the females with their wing-huds still ex- 

 tending downward. 



This is a fact of some importance and, as far as I am aware, has 

 never previously been noticed among grasshoppers. With it is 

 connected the fact that the males of the Eice Grasshopper almost in- 

 variably undergo one less moult, and therefore pass through one less 

 stage in development, than do the females, and this, in turn, accounts for 

 the interesting fact tliat, on the whole, tlie males assume the adult form 

 deeidedlv earlier in the season than the females do. 



SIXTH INSTAR. (PLATE I, FIG. 7.) 



Length of body ... ... ... 17'5 — 19 mm. 



Length of antennae ... ... 8 — 9 ,, 



Number of segments in antennae ... 25 — 26 



Colour. — Colour variations as in the previous instai'. 

 Males of this instar show, with very few exceptions, a marked de- 

 velopment of the wing-buds (see Plate IV, Fig. 3) which have grown 

 backward to cover over the first and part of the second segment or 

 division of the abdomen (length of forewing 6'5 mm.). In the case 

 of all males of the sixth instar which have reached this stage of 

 development, this is the final instar. With the following moult the 

 adult form is reached. 



Females of the sixth instar have, as already noted, all the general 

 appearance of the males of the previous instar except, of course, that 

 they are larger and their antennae are longer and contain move 

 segments. The wing-buds are folded upward for the first time (see 

 Plate IV, Fig. 2). 



SEVENTH INSTAR. 



In tliis stage are to be found, for the most part, females. In 

 rare cases, males are to be found which also pass through this stage. 



Length of body ... ... ... 27"5-30mm. 



Length of antennae .. . ... ... 11'5 ,, 



Number of segments in antennae . . . 27 — 28 



The wing-buds resemble in appearance those of the male in the 

 sixth instar but, of course, are longer corresponding with the greater 

 sixe of the individual (length of anterior wing 8 mm., see Plate IV, Fig. 4). 



It is interesting to compare the length of females of this instar 

 with that of adult males of the same age and reared in the same jar. 

 These latter had a length of 26 — 27 mm. or almost the same 

 as that of the females. It seems fairly clear, therefore, that, in the case 

 of this species, the almost uniformly greater length of the females is to be 

 accounted for by the fact that they undergo a longer period of growth 

 and development represented very definitely by an additional instar. 



In connection with measurements of length in developing and 

 adult grasshoppers of this as well as other species, it must be pointed 

 out that the length is subject to considerable variation and the above 

 figures must be taken as applying only to the grasshoppers actually under 



