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TEXT-BOOK OF ENTOMOLOGY 



These observations on two widely separate groups of Diptera were confirmed 

 by Landois, and afterwards by Pancritius, for the Lepidoptera, by Ganin for the 

 Hymenoptera, by Dewitz for Hymenoptera (ants) and Trichoptera ; also for the 

 Neuroptera by Panctitius. In the ant-lion (Myrmeleon formicariut) Pancritius 

 found no rudiments of the wings in larvse a year old, but they were detected in 

 the second year of larval life, and do not differ much histologically or in shapi- 

 from those of Lepidoptera. In the Coleoptera and Hymenoptera the imaginal 

 buds appear rather late in larval life, yet their structure is like that of Lepi- 

 doptera. In Cimbex the rudiments of the wings are not found in the young 

 larva, but are seen in the semipupa, which stage lasts over six weeks. 



The general relation of the rudiments (imaginal buds) of the wings 

 of a tineid moth to the rest of the body near the end of larval 

 life may be seen in Figs. 142, 143 (Tinea ?), the sections not, however, 



W ! 



FIG. 143. Section of the same specimen as in Vig. 142, but cut through the second pair of wings 

 (w) ; i y mid-intestine ; h, heart ; fb, fat-body ; I, leg ; n, nervous cord. 



showing their connection with the hypodermis, which has been torn 

 away during the process of cutting. That the wing is but a fold of 

 the hypodermis is well seen in Fig. 144, of Datana, which represents 

 a much later stage of development than in Figs. 142 and 143, the 

 larva just entering on the semipupa stage. 



In caterpillars of stage I, 3 to 4 mm. in length. G-onin found the 

 wing-germs as in Fig. 145, A being a thickening of the hypodermis, 

 with the embryonic cells, i.e. of Verson. on the convex border. 

 The two leaves, or sides of the wing, begin to differentiate in stage 

 II (C, Z>), and in stage III the envelope is formed (E), while the 

 trachese begin to proliferate, and the capillary tracheae or tracheoles 

 at this time arise (Fig. 145, c). The wall of the principal trachea 



