Another disadvantage of these volatile substances is that if used in too large quantities they will, in delicate specimens, especially beetles, cause an extension of the soft ligaments between the head and prothorax or between the latter and the mesothorax, and thus bring the specimen into an unnatural position, or cause the head, or head and thorax to drop off.
"Directions for Collecting and Preserving Insects"
C. V. Riley
For, out of the many specimens which have come under my observation from various countries of Europe, if there is one point more constant than another in this otherwise variable species, it is, I believe, to all circumstances, its immaculate prothorax.
"On the Variation of Species, with Especial Reference to the Insecta ; Followed by an Inquiry into the Nature of Genera"
Thomas Vernon Wollaston
The prothorax bears the first pair of legs.
"Butterflies Worth Knowing"
Clarence M. Weed