Of the several pretty-clear images I have seen of telegraph lines that were strung within Chicago during the early years of the telegraph, all appear to have had their wires attached beneath their crossarms, very possibly via non-pintype "ramshorn" style insulators as evident here.

Gradually-shorter crossarms from the poletop downwards also apparently were the construction standard of the telegraph company who owned this line and the others I have seen built with this technique in the Chicago vicinity.